Double check - there are TWO different SP-01s. The standard SP-01 is steel frame with night sights, and the SP-01 Phantom is poly frame without night sights. I have the Phantom, EXCELLENT pistol.
I have seen it for sale below $500 on Buds on sale, but not very often. If it is NIB, go for it, but see if he has an extras with it, holster, extra magazine,etc.
A fantastic place to get holsters is High Noon Holsters, who make rigs for both the standard SP-01 and the Phantom, as shown with my Phantom below. This is the rig I am wearing right now, insanely comfortable.