74 240D. Gem or rock?

[Jas2on]

On my way home today I saw a 74 240D for sale in a used car lot. It caught my eye cause it was so damn beautiful. No scrathes, dings, dents or anything. Interior was almost immaculate. No rust underneath. Engine looked clean, almost too much so.
It started up with a little effort with some black smoke, but then idled white. I took it for a spin, transmission seemed nice, but still smoked white. Is that serious? He wanted $2800 but when I said it still smoked too much, he said $2200. No records come from the car, but he said they got it at a local dealership who someone traded it in for.
Cant seem to located the VIN number. Just a bunch of numbers inside. Any suggestions? What else should I look for?