Yeah he's moving up from 154 when he really just got there. And he's fighting a guy who could easily compete at 168. Spinks doesn't have the range to win on the outside, so he's going to have to come inside, he'll probably be lunging into the inside not landing much for the first 5 rounds without getting caught and just holding on. JT will eventually catch him coming inside and KO him.

Overly simplified a bit, but that's the jist of what I think happens. JT wins easy, maybe the scorecards are even halfway through the fight. But no real challenge for JT imo.