You think Gus can do what no man has ever done? I think you are insane. Hendo's jaw can take anything Gus has to offer. I don't feel as confident the other way around. Gus could very well win, but he wouldn't TKO Hendo, not now, not ever. Gus won't even crack the top 5 in punching power that Hendo has faced.
Hendo is 41 and got knocked silly in his last fight, he said himself that he was KO'd on his feet in the 4th round against Shogun. The only thing certain in this sport is that nothing is EVER certain.