Without looking at the engine codes (which you should do), you can get an idea of whether or not it's a W72 engine by the chrome valve covers, and the plastic air intake piece that fits on the air clener (the standard engine doesn't have that piece).
If you're just picking up the car, ask the guy if the car has the original carburetor. If not, ask him if he has it laying around somewhere....they're really hard to find.