Technically, Gus is a really good boxer. I can see Gus winning this fight if it goes through. I mean, this fight is probably as difficult for Lewis as it gets. Lewis will always have puncher's chance against anybody at heavyweight. Gus probably would be better boxer than most at heavyweight.
At first I thought Lewis would dead Gus, but we will have to see. If Gus that fought against Jones shows up, Gus would have a better chance against Lewis as much as anyone at heavyweight.
I mean, like I said, UFC gives no fucks about what's fair, so I can see them putting this fight on the same card as Jones vs Ngannou.