Federer will probably win now
Well the fact that this isn't a grand slam final--with the potential of 5 sets might have a little something to do with it. Plus, from my observation, Roger doesn't necessarily expend a lot of energy in some of these tournaments. Plus, Roger is coming back from a break. And Andy has the winning record in the the match-up!
So it would stand to reason bookies would pick Andy Murray. But it's not necessarily because he's the "better" player. He might be the player with more of the desire to win this meeting though.
We shall see. It wouldn't shock me if Andy won. But to me, it wouldn't saying much about whether or not Roger is going to win the U.S. Open. To me, Roger is the favorite there.