What version GAL is installed? They are on the upper right part of the board. I think only the "A" GALs were incompatible with ROM 3s.
Edit: GSPLD1A is for ROM 01 only, GSPLD1B is for ROM 3 only. GSPLD2A doesn't get changed.
If you have a card with GSPLD1A installed in a ROM 3, you will have memory mapping issues.