Been three years since I poured anything in anger, so my memory is a touch hazy on what is in stock, but, fairly sure I did the '64 GP wheel from the kit.
The tell is a conical center cap, versus the flatter cap of the '65 - '68 that is in all the MPC kits from that era, and a the AMT '65 GP.
I prefer the '63-'64, which looks more finished; had a restorable set that were going to be added to the '66 2+2, right before I got an offer I couldn't refuse ...