So, like many this is my first post here on RWG and I'd really love some thoughts on the Rolex I just bought. It's an 5500 Air King, that based on the serial dates puts it's production between late 1978 and early 1988. When I opened it, I was surprised to find a 1570 movement, rather than the 1520 I've always associated with a 5500. The movement no. also dates it to the same time frame. The interesting part that I then noticed is that this 1570 is a non-hacking movement. From everything I've read on other posts on here, I thought that the non-hacking 15XX movement was done away with in the late 60's, but this watch is late 70's. I took it to my watch guy who's a licensed to service Rolex and in his opinion, he feel's it all factory, not a mod to non-hacking (the channel finish is exactly the same as the surrounding). My question is, has anyone else come across a 5500 Air King with a non-hacking 1570 movement? What's interesting is that it looks exactly as my late 60's Explorer 1016 1570 movement. I would love to hear from anyone who's seen anything like this. Cheers.