I have a 1940 Chevy WB 1-1/2 Ton truck my grandfather bought brand new. It has two 1" or so diameter holes above the window on the door. This was for the rear view mirror brackets. According to my Dad these mirrors jiggled around a lot and the driver's ran into them since they stuck out past the running board, so many of them were tossed. I had to look around for a while to find an original one to put back in place.
