Rearview mirrors were not stock. They were either added by the dealer or by the owner. I have a more modern mirror on my truck, which is screwed to the pannel above the windshield.
You can find mirrors that look more period from many of the usual venders. These would look more original than mine but my truck already had holes drilled for the one I'm using. No mater what kind you get you are going to have to drill some holes to mount it.
George
