According to the factory assembly manual, there needs to be a "reinforcement assembly" on the inside of the door that I guess would be there to help hold the mirror arm on securely. It does not give the measurement from the door edge to the screw holes though. However, to give you a rough idea of where the mirror sits, the 2 back screws for the mirror are pretty much lined up under the vent window frame between the 2 top body crease's (if thats the right term!) I don't know if your truck would have the "reinforcement" for the 3 screws,if it came with the camper mirrors originally, maybe not- but you might be able to use a flat piece of steel behind there to button it all down if you use machine screws with nuts and washers. I'd post a picture for you on here if I could, maybe someone else could do this-the mirror diagram is almost at the back of the manual, about 40-50 pages from the back. Hope this helps-KEEP ON TRUCKIN!!!!
