I don't think Manny is risking his record by facing Floyd at 147 at this stage in his career. Win, lose, or draw. Also, I think it's pretty obvious that he wants the fight.
I agree with what said you except that Manny has no qualms losing - he's been there, done it. It's Floyd who is very wary of the risk involved in fighting Pacquiao.
Even if Manny thought Floyd had a good chance of beating him, he would still want the fight because that's the fight that the fans want. I don't think he's the kind of fighter who is afraid to lose.