Not a Pontiac but my first car at 16 was a '63 Impala that had the radio speaker in the back seat with that metal grille. I rigged up a blue light behind it so I could turn it on from the drivers' seat. I thought that all those little perforations in the grille made the headliner look like a disco club..it didn't but I still had a cool blue light in my car....lol
Found a pic-
