[njsteve]

Originally Posted by njsteve

The Jan 1st 1972 could have been a mandated date for the newer lamp assemblies based on the new Federal safety laws - i.e. all front signal lamp lenses now have to be amber, all tail lenses have to be red.

Now that I recall, I remember that Chrysler changed all their side marker lenses on their cars in 1972 to the big, standardized rectangular red and amber reflective lenses. The same Federal guidelines that required the Chrysler change might have been part of the reason for the Firebird change to the amber lenses as well for '72.