My header was damaged slightly. It's really SMC, or a type of polyester resin, similar to fiberglass.
Fiberglass is easy to repair, the only troubel is allighnment if the panel is split.
I don't have any problem " Ruining " a header panel, only beace you can find them pretty easily, as everyone is focused on the 70 & 71. Personally, your idea of incorporating the "new" Challenger grille and the old header panel is a very worthy idea. I had discussed this with my friends at work previously. They too, liked the idea.
I will attempt to see what CAN work.
dan