It's two masters in there, so I wouldn't bet on any outcome. Jersey Joe wasn't quite as fleet-footed by 1950, while Moore was close to his best as a fighter. I see Moore putting on more pressure and working consistently, with Walcott looking to counter and using his strength in close, but Moore was an adept spoiler himself. Fighting big heavyweights didn't bother him, he never wore himself down. Essentially it comes down to who is able to fight their fight.
Sure...but look what he did offensively to Harold Johnson, Ezzard Charles, and Rocky Marciano? I think Walcott was fighting at his best offensively during this period, which could spell doom for Moore. Walcott still had his waltz, and his feints even if they were slightly slower, and he still had that top jab. If Charles and Patterson could flatten Moore, I see no reason why Walcott couldn't. Archie just never could beat a great heavyweight. I doubt he would break that track record with a master boxer puncher like Jersey Joe.
Harold Johnson was young, always a bit suspect and he did suffer a legitimate injury during the bout, whether it was caused by a punch or not. Charles got caught in 1 out of 4. I think the chances of Walcott catching Moore and KO'ing him are greater, but it's by no means set in stone. Moore was a great defensive fighter and was KO'd once out of 3 against Charles, only because he was aggressively going for the knockout until suddenly getting knocked out himself. Walcott, despite his offensive display in the first round against Marciano, was not an aggressive fighter and the Moore of 1950 was more cautious, having learned from previous experiences where he had allowed himself to get caught. It took a relentless Marciano to KO him and a blinding fast Patterson when Moore was 40+ years old. Charles forcing the issue here while Walcott tries to pick his spots: [ame]http://www.youtube.com/watch?v=5VfAlEwl35w[/ame] Moore taking the fight to Valdes: [ame]http://www.youtube.com/watch?v=Fi66CQ_ivDg[/ame] If it comes down to sheer workrate, Moore would be taking it. Walcott however has the chance to discourage Moore from coming in with his powerful counters. As I said previously, the one who is able to fight their fight would likely end up the winner. Both are masters of their craft, so I wouldn't count out either of the two completely. Moore can really offset Walcott, especially an older Jersey Joe, and force the issue while avoiding any of Walcott's "set-ups" and making him fight at an uncomfortable pace, which is why I see him having a chance here.
I think that Walcott has a better chance of scoring a KO, and he could also win a decision by controlling the fight and discouraging Moore from coming in. Moore's chance is to plain outwork Walcott over the distance and avoid Walcott's power. Layne had none of the defensive ability of Moore, but his awkward style did trouble Walcott. Of course Layne also had the chin to take a good punch, but for the most part he prevented Walcott from getting set, whether intentionally or by mistake. Moore is going to look to do much of the same.
I'm going against the grain here. I think Moore would be able to beat Walcott to the punch, and give offense attacks at the right moment to ride home with a close decision victory.