I think 2006 Federer beats 2010 Nadal at the US Open to be honest, matchup issue or not
He might beat him on fast hardcourts for sure, but overall advantage Nadal due to their matchup.
That said, if Nadal serves like USO 2010 doubt Federer would beat him anywhere, even indoors to be honest.
Federer loses to Nadal when Rafa is serving like a WTA player; now add tons of free points off serve and do the math, things definitely don't look good for Federer. I have to wonder why Rafa stopped serving like that, he was downright scary in USO 2010.