I know the factory painted the front of the radiator support black on Grabbers/Comet Gt to hide the body color behind the black grill. It is possible they painted all of them for a time or it was a mistake and they let it go. Different assembly plants did things a little different. Rustproofing is a good possibility. Workers in the paint shop would check broadcast sheets to see what model was next if it was a Grabber they applied the black out paint. Mistakes were made. That's why today they want everything the same to insure quality.
