On the interior parts I would say you would have to make some consessions and reupholster the best you could. Heck I am making some aluminum diamond plate interior door panels for my '80 I think people would dig those in a 1st gen.
The biggest problem I can see with my plan is that I would want to keep every truck I rebuilt. Maybe I would be better off just finding them tuning them up and doing a quick flip rather than investing the time to completely redo them. There are quite a few out here just wasting away but most aren't for sale because nobody wants to take the time to dig them out and there is absolutely NO market in this area.