A few years back I found what was left of a 1957 Chevy in and old junkyard. There was a strip on the side near the end and it was without a doubt stainless steel.

I guess the automakers went to chrome when it got cheaper or made the car sell better.

I do remember a time when auto dealers referred to any trim such as that as 'brightwork'. I guess that way no matter it was made of they could advertise it.