http://www.carandclassic.co.uk/car/C172978/It's a black manual. It has grey wheels, so - you are correct - "should" have a gas flap hood. Either it's been swapped with a plain hood for money, or the original has been damaged beyond repair.
I would guess the car is a fresh import - he is a car dealer I think? - certainly has sold a couple of DeLoreans recently (unless it was the same one twice!) as well as a few DeLorean parts.