Update: I found this in one of my old threads, it was posted by 94 Teal GT:
To follow up what HairyCanary said, the door jamb sticker will have a section that says AX. The letter stamped in that box will tell you what it was equipped with from the factory. His 3rd method is the best way to know for sure w/o having to open the cover.
M=2.73
E=3.27
Z=3.08