NOS gas cap is pretty, but here's another point I suspect we might already have discussed in this lonnnnnnng thread. I suppose this could vary by build plant, but (on cars from some/most/all plants?) the factory-installed cap was fully painted body colour in 1965. The service replacement gas cap2074 054, the one you're showing hereis identical except it's chromed so it goes fine right out of the box with any car colour.
(My favourite factory A-body gas cap finish is as found on the '60 Valiant and possibly some other early A-bodies: car-colour cap body, chrome handle bar).