Can't find the exact date but I'm assuming it would've been late-70s. That's going on the below evidence.

Here's the board:

It was shaped for Peter Lawrence who features in this Hot Stuff ad (at right):

Always liked this shot of Mick on a singley. Lacks the heft of Parko's but it's razor sharp.

Here's the photos of Dave's 1982 AB-shaped Hot Stuff (see above). One of AB's first Thrusters.

No reason it couldn't have been '82. Simon rode the Thruster in '81 to immediate acclaim and a raft of shapers quickly followed suit. AB surfed against Simon in the '81 Pipe final. Came second, and probably should've beat Simon, then went straight home and shaped a Thruster, according to this interview:

"I was riding a six channel single fin [in the Pipe Masters final against Simon], it was the last swan song of the singles. After that I went home and built a thruster, and that was it. I never rode a single fin again."

So if it was '82 it would've been one of AB's first Thrusters but it's possible.

The aforementioned interview is from Damaged Goods. Here's a great li'l excerpt (with full interview here):

When did you decide to shape your first channel bottom and single or thruster?

When I came back from Hawaii that year. I didn’t like those curved channels but I understood the concept. Then Col came back to Aus and he changed and built clinker channels, based on a water ski boat.

That was when I went like, “I get it. That’s what I wanna do.” So I just started building them.
I meet up with Col at the first Stubbies in Burleigh—we just clicked and my wife clicked with his wife and we became pretty tight friends. He showed me how to push them in better and then I just kinda locked into it and then he died when he was only 31! So I pretty much I carried the flame ever since.

I take it you developed these channels into the hard edged six-channel?

Nah, they where clinkers. They were the straight ones, but I didn’t know. I was just putting them in shallow because I just wanted to try it out, so I built these shallow channels…

The funny story was: I went down to the Coke Contest at Narrabeen. I got in the quarter finals of it and I was riding my board right up until the quarters and I was walking down the beach and worrying, going to myself, “Fuck they are shallow man.” Col had one of his boards with big, deep, fat-ass channels in it and it was leaning on the fence. I had my singlet on and was running down the beach to jump in the water I looked up and I saw his board and just dropped mine on the beach, ran up and said, “I’m taking this,” and I paddled out. I’ve never done that.

I ended up beating PT [Peter Townend] on it and that’s when it changed. Col came in one day when I was shaping and I was trying to push these channels in you know? You do all these different, weird methods and he just goes, “What are you doing?”
“I’m putting channels in.”
And he goes, “Get out of the way,” looks around the room and finds this block and goes, “Ok this will do.” And kissssh (sanding sound) just buries into the board. Then he finds a block and puts some paper on it goes, kissh kissh (sanding sound) and goes, “There. That’s how you do it.”
I was like slack-jawed going, “Fuck no way.” From then on I still used the same method.

You were still running these channels through a single fin set up?

Yeah, what happened was that Col liked single fins, I liked thrusters and umm, so we kinda split there and I changed how they sit in the bottom and built them to work with the three fins. I ran the short outside channel and long inside and he ran the opposite. Then I went into perfecting the thruster version of it. I went, “I’m going to ride them,” and everything, so I built them.

[Prior to this] I had a 7’2 and 7’6 at Pipe. That was quite a momentous time. It was classic, cause Simon [Anderson] was introducing the thruster and in the Pipe final there were two of the most revolutionary designs in modern surfing competing against each other. He had the thruster and I had the channels. They are two things that are still in design to this day you know? I was riding a six channel single fin, it was the last swan song of the singles. After that I went home and built a thruster, and that was it. I never rode a single fin again.

Can you tell us a bit about that day in 1981, the Pipe Masters final?

Yeah, one of the funniest things was that it was a bit smaller in the morning and Rabbit [Bartholomew], I made Rabbit’s boards back then. He had a 7’2 and I had a 7’6 and I wanted a bit smaller board so I said, “Oi, lets swap boards.” So I rode his 7’2 and he rode my 7’6 and during the day the swell got bigger and bigger. Fuck it was capping second reef, and we were standing there waiting to go out in the final and this giant set comes through, I just looked at Rabbit and go, “Fuck mate I want my 7’6 back.”
And he just went like, “No no no no…you have done really good on the 7’2. Stick with what you have, go stick with what you’ve got,” and he wouldn’t give it back to me.
So I just went, “Fuck I’m just gonna have to ride it.”

And the seven man final?

Yea that’s another funny thing, and everyone knows this story now.
Buttons [Kaluhiokalani], he’s Hawaiian, and they had the Da Hui – the power group. They where kinda like a group of thugs you know? Anyway, they were all down there cheering him on. He should have won the semi final, but 10 minutes before the heat finished, he dropped in on me and I had to straighten out. He got smashed and i didn’t think anything of it. But when i came in they announced the results and it went, 1st was Rabbit, 2nd was someone, 3rd was me and 4th was Buttons.

Da Hui just erupted and they came running down and threatened to tear the judging towers down. “We’re are gonna shut this thing down and beat everyone up.”
“Fuckin’ no way man. No way”
“Get him, Al Byrne, it’s his fault.” Ya know?
And I had friends in Da Hui and they were going, “Fuck it’s not AB’s fault, leave him alone.” So we were just terrified and then Fred Hemmings and Randy Rarrick had to sort things out.

So Fred comes up and gets me and Buttons, hauls us about 100 yards up the beach, away from everyone and sits us down and goes, “You to guys keep away from each other. Whatever you did, don’t do that again, I can’t afford to do this, but this is what we are going to do. Buttons is gonna be in the final. It’s gonna be a 7 man final.” And everything was all good.

Anyway we paddle out for the final and the very first thing Buttons does is drops in on Bugs [Rabbit] (laughs). The very first thing! And the judges were too scared to call a drop in on him, so he ended up coming 4th or 3rd in the final.

And so you came 2nd?

Yeah…and then the aftermath of it all… I’ve never been on a podium before. I didn’t know what you were supposed to do, so I just got my cheque and walked off. Anyway me and Rabbit and Chappy Jennings were gonna go up to Turtle Bay for dinner and I hadn’t eaten all day and guys were giving me champagne and shit.

We get up and Bugs goes, “Oh Simon’s having a party at his Condo. Let’s go there and we will just have one drink with him and then go to dinner.” Anyway we get to Simon’s place and it was mayhem. The boys were playing this game Animal Thumpers. It’s a drinking game and they had like a 10oz glass and were filling it with straight sprits and if you didn’t make your right animal noise you had to skol a whole glass of sprits, right?
So I’m not playing and someone just passed out vomiting and they go, “You’re in Allan,” and dragged me down and then they just whaled on me. I ended up drinking like, two full glasses of sprits. Then the next thing I start spinning and I go up to Simon’s bedroom and go to lay down on the bed and threw up in the bed, so they tell me. I threw up over the balcony, down onto all the guys standing underneath and so on.

Anyway the next day I was so fucken hungover and Berny Baker came to me and said, “Allan, the head of Lighting Bolt wants to meet you,” and that’s when Lopez and MR [Mark Richards] were sponsored by them, “And they wanna sponsor you. You’re their new guy”.
And I went, “Ohhh, um I can’t go… I’m too hungover.”
And he was like, “You got to man. It’s gonna change your life.”
And I was like, “I really can’t go today.” So I didn’t go and then the whole thing fell through.

I watched the 81 Pipe finals footage the other day and from my opinion you clearly had the best barrel of the Final. If judging had of been different back then, using today’s top two wave system, things may have gone your way?
Ha, yeah to this day no one could believe I didn’t win. I still go there (Hawaii) and guys that were there on the beach that day, like I’ll walk into a restaurant or be walking down the road and had people stop their car and go, “You were fuckin’ ripped man. How do you win a pipe contest and not get barreled?” (Referring to Simon who won).

They just had Simon’s book launch recently and Simon goes, “The deal is I won, he came 2nd – end of story.” (Laughs) But Simon’s the same; he doesn’t understand how he won either.

It was the beginning of the thruster. Simon was meant to have won it the year before and he didn’t and they wanted him to win, so they just made it happen. But I think I got more mileage out of coming 2nd because it’s been one of the most controversial decisions in pro-surfing.