All of the Duster/Demon/Dart Sport deck lids are the same with on exception. '70 and some of the '71s were flat while some '71s and '72 and up cars had a body line down the middle. The nice thing about owning a '71 like yours is that you can put either one on and it would be correct.
Cut out for wing was available in 1970, 1971 and 1972 possibly 1973, no idea why some trunk lids had them and some not.
Chrysler may have ordered too many compared to how many cars were ordered with this option.