In the meantime, there’s some evidence that Intercontinental distributors hated the inconsistent and often illogical numbering techniques of their Swiss overlords. When the crystals over the 160xx era of Datejust watches remain comprised of acrylic, the sloped "pie pan" model dial from your prior technology is gone, and changed by https://www.watchesworld.com/a-history-of-watch-reference-numbers/