The new Heritage rear body panels have a pair of rather large holes to accommodate the late model panel mounted license plate lights. The '72 didn't have these holes since the lights were mounted to the bumper overriders. So It's necessary to fill in the unwanted holes.
Plugs were cut from 20g sheet with a hole saw, and clamped into place for the first tack weld.
Welds done and ready to grind flush. The welding will have caused some heat shrinkage to the panel in this area causing a depression. So after grinding smooth it will be necessary to planish it a bit with hammer and dolly to raise the metal.