[IronCanine]

Ok here are some 70s. The inner grille has horizontal "stripes" that are raised and arranged in columns and highlighted in silver against a black egg crate.

Again, notice the paint at the edge of the parking lights. Here you can see a variation. The first pic is the 80 mile barn find truck (known original) it has the two stripes painted to the end. The others show the black blocked off. My feeling is that this is just a manufacturer variability and either way may be considered correct. More detailed data gathered from know originals is needed to get to the bottom of that. Whether or not it was a variation among suppliers or if it was a model year change (ie before or after a certain serial number).