Do you have a locked SNES system? If the PowerPak works then that is the region.
Otherwise you can look at the back, there is a sticker inside that starts with RET-. Next is either SD- (DSP chip) or SN- (no DSP). Then the region USA (NTSC) or PAL (PAL) or NON (no lockout).
Final way is to open it up and check if the lockout is D411 (NTSC) or D413 (PAL).