69 dart gt seats,tracks

"U.S. National Highway Traffic Safety Administration (NHTSA) required that all new cars sold in the U.S. after January 1, 1969 be outfitted with head restraints. The U.S. regulation, was known as the Federal Motor Vehicle Safety Standard 202."
So head rests that were optional before January 1, 1969 became a standard item in all cars built after that date.