If you look at the very last ISA slot, on the edge facing the end of the motherboard, there will be a sticker detailing exactly which motherboard it is. The downside is that if it is already in a computer, you'll have to pull the mobo out to see the sticker.
IF you can get a dentist's/mechanic's mirror, perhaps you can slip it in a see well enough to read the sticker.
Good luck,
Joe