Chrome 71-72 bumper guards difference in old & new

[Arrington01]

I am trying to get some clarification on the old chrome bumper guards as in what do 1971-72 GM ones look like compared to the new repop ones. Is the metal thickness different? The shape? I know supposedly the early ones had
Smooth rubber pad. Some say the design rubber pad is aftermarket or was GM's later year production style. By the way I am looking to buy a old set to. Any knowledge on this would be appreciated.