when you bought it, did the auction say GTS or GT? and if the guy had it on his car im pretty sure he's not a moron and would put GTS when his car was a GT. y dont you just install it and find out. i wouldnt want to wait around if i were you.
*2003 Black GT-S 6speed* TRD body kit, HID upgrade, clear corners, Matrix XRS shift knob, 02 tails, trd exhaust, AEM gen 2 CAI, TWM short shifter.