You probably have a rev 1 board (they will work with the 66mhz bus speed chips). I think the originals have rage LT video chips while rev2 have rage 3d (might be a difference in VRAM size as well). The originals had sloped plastic on both sides toward the clasp, rev2 had a cliff on the top section.
Many people swapped parts and displays over the years so you have no idea what exactly you have and if it is factory stock.