They should... Were the moldings color matched to the car or painted?
To my knowledge they should all have black trim. I am looking at a 1991 model. How do I know its a genuine numbers matching car?
Check the VIN on carfax and make sure there are VIN stickers on the trunklid and front fenders Is the BMW dealer a good place to take it for a mechanical check (compression and leakdown and general check)?
It all depends on the dealer, go to any mechanic you trust ( that knows something about BMWs) for your prepurchase inspection