I really don't think you can make that assumption until he fights a worthy opponent. He took a former judo champion down within seconds of the first round and made the guy tap by ground and pound (not ref stoppage) which is very rare.
The questions are: how well can he take a punch and how well does he do on his back? If his training has went as well as he and his camp states, his ground defense may be pretty good.
So the real question lies in his jaw.
He's the first heavyweight to combine size, strength, speed, and actual talent other than being a brawler ie: tank.
As long as he finishes and doesn't lay and pray like a lot of people with wrestling backrounds do, I think he's gonna do well.