Interesting reading.. I have no knowledge of the painting methods used on Camaros, but one thing seems strange to me, based on my understanding of the paint methods used on passenger cars from the early '60s (partly thanks to Mo's Dad).
The firewall paint was a primer, which did not require baking. On those cars, the body was painted first, then it went through the bake oven. After that, the sides and top of the cowl were masked and the firewall was painted. And on those cars, the cowl tags were always attached just before the car went to paint. The metal under the tag remained the original primer/sealer.
I suppose it wouldn't hurt to bake the firewall primer coat if it was painted first
Verne