Rear Air Differences in Same Model Year?

Top one is likely aftermarket, or possibly repurposed from a different make, looks a lot like the one in my 76 Pontiac Ventura. The other one appears to be the same as my 1970 Dart had.

Looks like I might have to see if the package tray was cut for it then, I can salvage the sheet metal from the one in my parts car and make the setup factory again