In the meantime, there’s some proof that Intercontinental distributors hated the inconsistent and sometimes illogical numbering techniques of their Swiss overlords. Although the crystals to the 160xx technology of Datejust watches are still comprised of acrylic, the sloped "pie pan" design dial from the earlier era is long gone, and https://www.watchesworld.com/a-history-of-watch-reference-numbers/