So this is my first post and I'm hoping someone out here might be able to shed some light on my new Air King purchase. It's a 5500 with a serial that dates its it to late 1977/early 1978. The interesting bit I realized when I bought it is that it has the 1570 movement versus the 1520/1530 I've seen in similar aged Air Kings. After examining it some more, it also doesn't have the hacking feature that I thought was always part of a 1570, like the one on my 1016 Explorer. Has anyone ever come across this movement? I've looked through some of the older post and it appears that a 5500 Air King might have featured a 1570 in that time range, but I've never seen a non-hacking one. I specifically asked my watch guy when I had it open to replace the crystal and gasket and he said that in his 35 years of servicing Rolexes he'd guarantee it is an authentic Rolex movement. If anyone has any info on this or has come across one themselves, please let me know. Also, as far as I have researched, this would make this Air King an Officially Certified Chronometer, not a Precision like the rest of the Air Kings I've seen, right?