If i had to guess, they were probably gearing up for that being the next thing. Rear seat shoulder restraints. I have an original 68 charger sales brochure i bought somewhere back in 1985. It states in optional items shoulder belts front were optional, and shoulder belts in the rear were optional. Then it also states in the brochure that some things may change after the time of printing. I have never seen an A or B body with optional rear seat shoulder belts. Not sure if that ended up being an otion or dropped because the DOT didnt make it mandatory. Could have also been there because of european and british ..
You have now..