As CPL pointed out, the "records" weren't too meaningful. They were being broken every day in Beijing.
Better to compare Phelps to the other guys in the pool in that race.
8 guys competed between France and USA:
Jason Lezak (46.06)
Frédérick Bousquet (46.63)
Alain Bernard (46.73)
Fabien Gilot (47.05)
Garrett Weber-Gale (47.02) Michael Phelps (47.51)
Cullen Jones (47.65)
Amaury Leveaux (47.91)
So your argument for him being overrated is that in his last event final, out of 8 events, is that he didn't have the best relay leg? Well, you've certainly convinced me.