Here is how I am attacking the Remote Mirror Restoration. A couple of years ago, I started removing parts on my '67 Convertible. I started taking inventory of everything that I needed to either Replace, Restore or use "as is". One of the first things I noticed was that the Remote Mirror was showing signs of its almost 50 years of age. The base was pitted, and the Mirror Housing was starting to show signs of it. I then removed my Passenger Side Accessory Mirror, which I had purchased NOS in the early 80's, and installed in the mid-eighties. Surprisingly, it had "weathered the storm" rather well, even with not having been garaged all of the time, the previous several years in particular. It actually looked as good as when I installed it. Knowing that I would be redoing the car one day, I did not really expect the Passenger Side Mirror to survive very well, so I had picked up another NOS one in the early 90's, figuring that I would need to replace it. Now, I had an "extra" one, that I could either sell, or put back on the shelf once again, for "down the road".
At that point, I got thinking; what if.............. Sure enough, in checking the Factory Remote Mirror with the Passenger Side Accessory Mirror, the casting numbers were the same, and the gasket that came with it even has the large hole in it for the cables to pass through. It was now just a matter of swapping out the base and housing, and transferring the cabled Remote Mirror to the NOS housing. Yes, I'll probably have to end up removing the cables from one end, but I did this on my '66 years ago, and as long as you go slowly, it's not really that bad. In going this route, I won't have to worry about any "square edges" being rounded during the replating process, or getting a bad plating job, etc. And all of this is not even taking into account the cost savings.
Twenty years ago, or so, I wouldn't have thought twice about having my original Remote replated. However, today, there are not near as many platers that will do die cast, much less guarantee it, and when you do find one, you have to find out what process they use (it's my understanding that there are two or three different processes), and once you are satisfied as to how the end result will look, be ready to "pay the price". I recently had a die cast Spotlight Bracket (approximately 2-3/4" x 8") for a 1957 Ford replated, and had quotes from $120 to $185. This makes it a viable option to find a NOS Passenger Side Accessory Mirror to use to replace parts on the Factory Remote Mirror. As the same Mirror was used on Full Size Fords, Fairlanes and Falcons as well as on Mustangs, they do surface fairly often; usually for $100 or less, NOS. I'm sure this would be considerably less than having the original replated.
At least this might be something to consider. When I actually make the conversion, I may find that it was harder than it appeared; but right now, this is the way I am proceeding.
Bob