Since one of my '86 Veloce's rear view mirrors lost its glass, I decided to upgrade with this set from classic alfa:
There was no note on the website about different years having different mirror mounts, but that appears to be the case, as they do not appear to be a direct swap.
On my car, there is a set of M6 threaded holes on the door. The hole in the mirrors is sized at about M5. Of course, after I drilled out the holes to accept M6 screws, I realized that they also don't line up (don't mind the color difference- it is plasti dip, not paint):
It looks like the M6 holes are in a bracket secured by rivets behind the door, that looks like they might be adjustable. In fact, if you could move the threaded holes to the widest point in the oval opening instead of the narrowest, it looks like they would fit. However, they don't seem to move on their own. So, is there a way to do this? An adapter? Do I need to take the door apart to get behind the bracket? Couldn't find anything in a search. I suppose I could drill out and tap holes in that bracket, but I am a bit leery about drilling into the door and not sure I could make good threads with the space available.