Browsing around looking at parts for my slant 6.

I pull a fuel pump for a 72 Dart with a part number of 60577 at $XX.XX

Then I pull up a Fuel Pump for a 76 Dart and get a part number of 60576 for a different(cheaper) amount.

I pulled up the 76 Model year because thats what year engine is in my 72 Dart

Did the designs for those fuel pumps change over those years and what is the difference,is in the arm or is it internal?