My late uncle who was a club fighter in the 30's said they both had to fight with handcuffs on. I believe one was trained by Blackburn.
There is circumstantial evidence that Godfrey was exceptional. After Gene Tunney retired, Jack Dempsey said that he was the best heavyweight left. Haynes is a more ambiguous case. His reputation rests on beating up a shot Primo Carnera. I suspect that he was never quite among the best contenders.