Gas caps for Dusters

No they aren’t all the same
67-70 were I think all the same,
71 different
72 different again.

The differences are in the part that goes inside the filler neck. Depth and number of tangs.

Do a search on this forum and someone posted a clear picture of the differences

Edit: I’m in a good mood. I did the search for you, it’s in here: Duster fuel filler pipe difference between years