Possibly, he did look like a different weight division from weigh in to fight night. Pity he's probably still too small for 200lbs, the jump is huge, he might be best suited to 185lb I personally think he was tired rather than he was just trying to box, which makes me think he does worse in the rematch
Now that you mention It, he didn't score a stoppage in the 3 fights that went past 8 rounds. Maybe his punches looses some steam in the later rounds or maybe It's his lack of work to the body that disables him to wear his durable and cagey opponents down?