It's a fight that is undoubtedly taking place beyond it's peak in terms of interest. That said, they still have footage from TUF 6 that they can use to make it a fight that a lot of casual fans will want to see.
While Hughes is past his peak as well, I think he has more than enough left to handle Serra. While Serra did upset GSP, in no way does it reflect the true ability of both men; GSP went in totally unprepared, for whatever reason, and Serra managed to fight above his station. The fact is Serra isn't in GSP's league and, even now, he isn't in Hughes' league either. I think Hughes takes Serra down and makes his life a misery for three rounds.