Here's a question: Could June 1979 Duran of the Palomino fight have put on an extra 10 pounds and won the middleweight title in November 79 against Antuofermo (that Hagler failed to do)? I'd put money on Duran achieving that.
Certainly is feasible as Vito was a small MW and he could comfortably make the 154 lb if he wanted to.