Fliptop gas cap on a Duster

I have used the adaptors and flip top on Dusters, I have one now on a 76 Roadrunner F body. I like it myself. A nice flip top is worth a few more $$ than an ugly one, and I have more confidence in a oem one is good condition than a repop from where???? China!??
I think f a flip top added to an A body as a day 2 deal, like adding mags, fancy, valve covers, , etc