some of the body aspects on the utes did change from the early 70's models to the 80's in OZ. The earlier utes dont have rear bumpers below the tray, where as the 80's the rear body was had indents for these bumpers, i also found that the earlier utes rear back panels were different they were cut back alot straighter where as the 80 models were rounded at the back.

Then there are alos a few diffences in the interior of older utes, dash, inside door handles. also some differences like battery holders some were staright and someon angle etc

its a bit easier to spot these things when you have my ute 80model and two mates utes next to it 74 and 81

But other than those small things the utes were the same