Is the plate with the model number on the back of the ways or the right end? Had to ask.
There are part numbers cast into the various parts. See what those are, find a parts diagram and see what size lathe the parts match up to.
Measure from the center of the chuck to the top of the ways. If it's 6" you have a 12" lathe, if it's 3" you have a 6" lathe.