Where to find model number on old Wilton Bench Vice?

This is an oldie, probably 1950s or 60s. But it's in great shape except
for a missing jaw piece. I have seen several of these jaw pieces being
sold on ebay, and on another site that sells tool parts, but they want a
model number. I can not find the model number anywhere on it.

Anyone know where to look?

I do know this is a Industrial Bench vice, with 5" jaw.
I know it's this because of some pictures I found online, and I measured
the jaw.