John, I am about a year late in making this comment but I only just saw this photo while I was doing some browsing. I'm afraid that I have to tell you that you have mis-identified the vehicle. You are calling it a "Plymouth Mercury". There has never been a Plymouth Mercury. The Mercury has always been a high-end free-standing make (marque as you would say in the UK) manufactured by Ford Motor Corporation and ranked between the Ford and the Lincoln in status. This particular car is a 1988 to 1991 Mercury Grand Marquis Colony Park station wagon (North American term for what you folks in the UK call an estate car or shooting brake). A beautiful car and a great photo.