My 1941 1 Ton PU had no rear view mirror just side view mounted on the upper door hinges.
My 1946 1/2 PU had one mounted on the center windshield division bar. It was a pain because whenever you opened or closed the wind shield you had to readjust the mirror.
My 1946 Suburban had the mirror mounted to the bottom of the over head panel.
Take your pick, if no holes were drilled in your overhead panel you either did not have one OR it clamped to the division bar.
