Roadrunner or Not

Thank you, Diana's Dart, for getting back with us!
If everything on your car checks out - this thread may cause another chapter, or at least some asterisks, to be written in "the book"!!!
I might suggest that you have the vehicle checked over by a good body man with the instructions to look for anything that would indicate body work has been done. Welds nicer than factory, extra welds, reemed out bolt holes, bolt marks where panels have been moved, that sort of thing.
You might have a "1 of 1" that was made in late '68, hence the core support and (maybe) the trunk panel having been stamped.
C