There's nothing specific I've seen relating to First Gen Firebirds, but the GTO Restoration Guide has a lot of info.
The assembly process for all GM cars (aside from Corvette) was pretty much the same. The body came from Fisher, while the other components, like the heater box, etc. were sourced from different suppliers. There was an excellent article in HPP a few years ago that focused on a Scott Tiemann restoration, and he listed some details about finishes under the hood of a 70 Judge. I think that's when I first realized, by looking at original road test photos (in b&w) of 67-69 Birds, that many "black" parts did indeed have different shades of black.
I'm fortunate enough to have my friend Dave Armstrong's 1969 Firebirds to use as a reference. His cars are perfect, and they've won national Pontiac shows, including the Top Honors, overall #1, at the 2009 POCI/GTOAA show. Amazing, considering that show was about 70% GTO's and Judges, and had 1,024 Pontiacs! I've taken many photos of Dave's pristine 1969 Firebird 400 RA ragtop, and his 1969 Firebird 400 hardtop. Nearly every part on his cars is NOS.
This is probably the most fascinating article ever created about the assembly process. Thanks to the Camaro Research Group for this.
