My LGS usually charges $350 - $375 for VG SS when he gets them in. Mine and the last ones he had, SS, 4&6" went for those prices and they were VG >EX condition.
But more commonly they're $400+.
Tops would be $550 for LNIB in the a configuration I was lusting over and I just HAD to have a SS.
The GP is technically a better gun.