Joking aside, Joyner is desperately hoping his former club do manage to triumph at Wembley for the first time in 35 years.
It is no surprise; having played 613 times for his hometown – one record that is never likely to be broken – the black and amber is forever imbued in him.
A majestic player, who started out as a centre having signed in 1972, and evolved into a silky-skilled stand-off and loose forward as time passed, he is arguably Castleford’s greatest-ever player.
The high, among all of his decorated career, was defeating Hull KR by the narrowest of margins 15-14 in 1986, to claim the Challenge Cup for only the fourth time in the club’s history.
The then Castleford coach Mal Reilly famously tells how he could not bear to watch as John Dorahy lined up a touchline conversion attempt of John Lydiat’s injury-time try to win it for Rovers.
“Neither could I,” Joyner told The Yorkshire Post.
“I had my back on it. I was giving Martin Ketteridge a bollocking; they got that try from a scrum after he’d kicked the ball out on the full.
“He had all the field to kick the ball on and he did that.
“Gary Prohm scored in the corner but I do think we’d been the better side for the 80 minutes. Keith England had given an interception away just before half-time to put them back in the game.
“But it wasn’t a happy couple of minutes at the end…!
“And it’s absolutely been too long for us not winning the Cup since.”
Current coach Daryl Powell a Castleford fan in the Wembley crowd of more than 82,000 in 1986, will seek to correct that this afternoon when his side take on Super League champions St Helens.
Joyner, 66, insisted: “I do fancy our chances. It’s a two-horse race and – I know it’s 35 years ago – but we were underdogs when Hull KR were big favourites.
“And we have a decent record against St Helens.
“There’s a lot of similarities, I think, about us in 1986 and this team now.
“We didn’t play particularly well after winning the semi-final due to injuries, just like this one hasn’t now.”
Joyner and another hero of ‘86 – try-scoring former Great Britain centre Tony Marchant – visited Wheldon Road to speak to the players on Thursday before they boarded their coach and headed south to London.
Ever since Powell took over in 2013, he has endeavoured to improve the culture of the club, something he has clearly achieved, in part by reminding his players of the importance and relevance of its own history.
Unsurprisingly, Joyner – who scored 185 tries in a Castleford career spanning from 1972 to 1992 – was one of the first former players he courted to try and impart his knowledge and unite the past and the present.
“He did and that was nice,” he recalled.
“Not just from my point of view but with all players who have played: if there’s no history there is no club is there…?
“It should never be forgotten. Rugby league hasn’t just started in the Super League era has it…?
“You can go back to every club really. But Cas, for a small town – and Featherstone – they have had some great players come through over the years.
“Daryl just asked me to chat with the players and tell them about the experiences.
“I told them I don’t know how many matches you’ll play, but most of those games, you’ll never remember the team.
“But if you win at Wembley you’ll never ever forget that team and those blokes with you.
“Me and Tony Marchant went down yesterday before they left and I said the same sort of thing about that experience.”
Joyner, who would also go on to coach the club from 1993 to 1997, including the brilliant Regal Trophy final win over Wigan, had always aspired to play for Castleford where he moved when still a young child having actually been born in Belle Isle, Leeds.
Before that unforgettable day in 1986, their Wembley icons had been the victorious teams of 1969 and 1970, which included legends such as Reilly, Brian Lockwood, Alan Hardisty and Keith Hepworth.
“I went to both those finals when we won it,” recalled Joyner.
“I wanted to emulate Malcolm, Alan Hardisty and Keith Hepworth and we were lucky enough to be able to do it.
“It was fantastic. Nobody can buy those sorts of experiences. It’s something you dream of as a kid – playing for Cas. And winning at Wembley as well is something else.
“I do remember a good bit about it. Winning it stands out! But the whole week. Our preparation went great. We couldn’t have prepared any better. Just the whole occasion.
“Once we got there, people say it’s just another game.
“But it isn’t is it? It’s an iconic venue and iconic game. The Rugby League Challenge Cup Final.
“It’s a big thing still, for me anyway. I know the Grand Final’s taken over a little bit but there’s many a great player who has never won the Challenge Cup and probably never played at Wembley either.
“Mal had things he wanted to do and it all came to fruition. It all fell into place.
“Not by luck. By a lot of hard work and concentration.”
Both those characteristics will be key this afternoon if Castleford are to finally discover new icons.
Meanwhile, Joyner revealed he did come close to leaving Wheldon Road on a couple of occasions in his illustrious career.
He recalled: “When I first signed for Cas, John Sheridan was A team coach and he went to Leeds, around 1974.
“He phoned me up and told me that Leeds had agreed a price and did I want to go to there? He said they (Castleford) want to sell you.
“Eric Ashton was Leeds coach at the time but – around then – he left and Roy Francis came in.
“And he stopped all ingoing and outgoing deals so nothing happened.
“Then John (Sheridan) actually came back to Cas.
“But there was Hull KR and Hull around the 78, 79, 80 period as well.
“Cas wouldn’t sell me. I think I would have gone at that point.”
Ifs, buts and maybes. Is he glad he did stay as a one-club man or does he wish he had ventured further afield from his beloved Castleford?
Former GreatBritain international Joyner, who lives in nearby Wentbridge, reflected: “A bit of both really.
“It was different times then; when you signed you signed for life. I have mixed feelings really.
“But looking back, if I had have gone, I wouldn’t ever have had ’86...”
Maybe today’s players will be saying the same about ’21 in decades to come.
Either way, like Joyner, they will forever be part of this club and this proud West Yorkshire town’s rich history.