You can have a totaled out A/C repair it and the FAA is not required to look at it. It does get a little more difficult if the Airwortiness ticket was surrenderd. Then you may have to either get the FAA involved or get a DAR. not sure on that. There is an old mechanices saying. If you have a data plate you have an A/C. I have seen a log book entry where they replaced the fusalage assy. Logged it using the fusalage P/N.