Interior Rear-view mirror mounting

[dracko]

Anyone mounted up an inside rear view mirror in a truck that didn't have one before?

My '64 must not have come with one from the factory so the PO screwed one to the top of the dash

I have an original and am just wondering if there is bolts welded inside the roof that i need to hit with the mount screws or if i'm just gonna have to drill some holes and screw it to the roof. there are no indents or markings that look like they might be a mount location but figured i'd ask first.

thanks!