I am putting one on my 51 3100. It apparently had one at some point, cause there are the 4 screw holes on each side (in the door sill) for the dog-bone brackets, (and these are small holes). Far as I can see, these are/would be the only holes needed to mount the visor, shouldn't be any leak issues. Center support doesn't use screws, it clamps to the center windshield strip.
I was fortunate enough to happen across an original visor off a 1953 3100, the real deal, not a repro. bartamos is correct, compare an original to a repro, and you'll see. They are rare, and folks who have them for sale, know what they have. Nothing wrong with the repros, there are plenty of them sold everyday, they fit and look good, but they are not the quality of an original. Had I not happened across mine, I was going the repro route.
It's your truck, you're the one that has to be happy with it.
Mike
