I don't know much about the guy, but if I were in his shoes... I'd worry more about jiu-jitsu and wrestling than just gaining weight. I don't care how good of boxer you are, if you don't learn MMA, you're going to get eaten alive in an MMA bout.
And at 35... like it or not, you don't learn as fast at 35, your reactions are not as fast, and you don't heal as fast. Yeah, Randy did wonderful into his 40's, but that's one single person, and other than him, it just hasn't happened.
That's not to say that Vic will suck. Maybe he's done a lot of ground work, and could do alright. But I doubt he'll ever make it to the UFC, he'll probably do a small number of fights in a smaller org, then disappear from the scene.
Defecato, ergo sum.
Leading the Thiago Silva bandwagon