Thanks! The previous owner lived in Washington, so it might have been even closer to him before I acquired it. Oh wait, and you do too. I've been meaning to ask the Seattle area folks if they know the car. Haven't had a chance to get any very good pictures yet though. I got it in October just in time for the really good weather to set in.
My guess is that it was installed while Reagan was president, wait - make that while Helmut Kohl was chancellor. They did a good job with the install and it's a good quality piece, so at least there's that. At some point in their lives many of these coupes have just been "pretty old cars" before they started ascending in value again. I can see some youngish German buying it, but he really wanted a 635, so he "snazzed" it up with an aftermarket sunroof. I was probably that foolish once too.
-Dan