I have a question that's been nagging me for about 5 years. Back in 1971 I bought a 64 Sprint and it had the plain gas cap with the closely spaced ridges around the outside. In 2015 I bought another 64 Sprint and it has the gas cap with the Falcon Logo on the inside.

Which is the correct cap or was one or the other an option? I've attached pictures of both.

Thanks to all.falcon cap plain.jpgfalcon cap with logo.jpg