Thanks for having me here, I just got my first Impala 1962 2 dr HT. I had it shipped in from Omaha Nebraska, she runs and drives. Im here to learn all I can about this car as well as the other Impalas of this wonderful era. I'll be around.
Unfortunately I am not the man to ask about restoration questions. I worked on these cars when they where new as a mechanic, and as a racer, but I never restored one.
It sounds like you are talking about an engine lathe turned decal Used a lot on Pontiacs on their hot cars and on some Chevys. If it is that part would have been machined versus a decal as plastic and adhesives where in their infancy and America still employed tens of thousands of machinist to actually turn stainless steel metal trim.
If you are unfamiliar with engine turned metal here is a Chinese example for sale to dress up your car's dash or comnsole: