My 1971 Duster filler neck had three screws that held it into the 1/4 panel, it did not have to be slid in from the outside of the trunk shruggy
I don't remember how the filler neck installed in my Wife, now my Grandsons, 1973 340 Space Duster confused
My 1969 Dodge Dart GTS installs the same way my 1971 Duster did work


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)