Very small update. . When I put the car back together 20 years ago the mirrors were never right. The drivers side mirror was always loose and passenger side wasn't seated right. It took me a couple of hours mostly because the retaining bracket for the mirror fell in the door, but I had to swap out the plastic fitting that goes between the door and mirror. It seems they were backwards. Ended up having to remove the right door panel to get the clip out. Now that is is off I found the dynamat is not stuck solidly to the door anymore. The adhesive is giving way. It looks like I need to get some spray adhesive or brush able contact cement and re apply the dynamat. The door is a bit rattley right now. Not loose parts, like a tin can. That means other panel needs to come off. I have a spare set I think in the attic. These were NOS when I got them and other than the chrome tape coming off the plastic strip, they are in excellenT shape. Was thinking of having the old ones re done by an upholstery shop with something a little more custom....need to noodle that. Maybe better to put it off as a future project. Took a lot of experimenting to figure it out with swapping the backing plates and all, but the mirrors now fit better than they have since I got the car back 20 years ago. Nice little accomplishment. Not much, but progress.