have a 1970 charger rt and there was no built sheets under the seats, I want to rebuilt the car back to factory, how do I go about finding out what the built sheet said
You may be able to get a duplicate build sheet made by them. I don't know, you'll have to look into it. They do reproduce fender tags, so it's possible.
I would also look around the car more for the build sheet, they didn't always put them under the rear seat.