I'd run the guys phone number through google and see if it turns up in other ads. If he turns out to be a flipper passing themselves off as a car collector / private owner / enthusiast, I'd run away. There is nothing like starting a transaction out with a lie / omission of data. Real dealers state in the ad that they are dealers.

Other than a mileage history, ignore car fax and rely on an actual inspection of the car. CF won't pickup damage that a person paid for out of pocket. ( as in to avoid insurance going up )

Older front suspensions used King Pins rather than Ball Joints. On American cars these went away in the late 50's, I have no idea when MB got away from them.