I think Cottos demeanor is typical of his pre-fight history. I wouldn't read too much into it. If anything .. it burns him to the core and makes him fight harder to show everyone up. I don't think it will make a shred of difference. There's a big difference between the intent to do something and having the ability to pull it off.
Manny could obliterate Cotto/pull off a decision or Cotto could manage to catch him with a hard shot. Personally, I think its Manny's fight to lose, but either way, I doubt Cotto would say after a victory "Bob pissed me off when he said I wasn't the star... so I decided to not lose like I originally thought I would... the belt was so pretty, I had to win.. it goes perfect with my rhinestone versace shades!!!"

or after a loss, say:

"I was ready to kill manny, but then when i found out i wasn't the star at the last press conference, the shock to the system became too much me to handle and I decided to just go into the ring and wing it, ricky hatton style..."

Everythings that needed to be settled except for the weigh-in has been settled before now and its just downtime reaction before the first bell. Different guys just react different to it. Everybody gets a little nervous; some people mask it with a smile, content they did the work they needed to be ready and others might be all business and don't have that calm come over them till the bell rings; Others till they have survived the first punch or first round. Its different for lots of fighters.