Anyone can buy a part. The real reward comes from fixing the old part. I have gone to extreme, to the point of ridiculous measures to repair really worn out original parts. The most memorable was my door latches. If you can fix one of those babies, you can fix anything.
I can tell you worked on an AD and not an Art Deco. Good luck finding used stuff to replace missing parts for Art Deco trucks, especially if you're missing something that's GMC specific.