Need some help on working this problem out: A 1966 K code data plate (on the door) gives a build date of October 4 (04K)in 1965, but the date on one of the hipo heads reads 5K19 (October 19. 1965). How could the head be manufactured after the car was built? Is it because the data plate only indicates the scheduled build date of the car and the car was actually built more than two weeks later. Would this make sense? Any help appreciated. Thanks, Tim.