i'm wondering if when he said "case" perhaps he meant the coffin top that sits on top of a machine that is in a cabinet to keep it clean. i've seen a few like that. if you can get the serial number you can find out what model it is. could you call him back and ask him for the serial number before you go see it, just so you have time to determine the model? or if it's one of the newer ones they have the model number right on it.
i guess what i'm thinking is that if it was me, i'd want an interval in between seeing it, figuring out what it is and actually buying it.