Then there is the yellow ....


Seriously, I ask because one of the National judges told me recently that all one color and mostly orange. Of course he could be wrong. Plus the fact every Camaro shop that sells first gen parts has been selling these stamps for years so who know how many of these firewalls have been stamped.
I would be interested in what Steve and the guys in the Vintage Certification Program have seen
Just saw this thread, so sorry for the delay in responding. I have looked at hundreds of camaros and with the exception of two the PTB stampings were the same color. As shown above many have a T stamped below the trim tag with an X chalk/crayon marking as well. I would certainly call multi color inspection stampings the exception but they did occur.