Were headrests std. on '69 bucket seat cars?

I am doing my seats and found that the backs were dated right around the time the car would have been delivered... about a month after the time the car would have been built. Trying to figure it out. Maybe the car showed up without head rests, the customer complained and the dealer installed a pair of backs with headrests?? Anyway, the bases were dated correctly for the car and the tags matched left and right and the seat backs each had the same date on their respective tags albeit, with the later date....

Just looking for peace of mind..

Thanks