In the meantime, there’s some evidence that Intercontinental distributors hated the inconsistent and infrequently illogical numbering techniques in their Swiss overlords. When the crystals over the 160xx generation of Datejust watches remain made out of acrylic, the sloped "pie pan" design and style dial within the prior era is gone, https://www.watchesworld.com/a-history-of-watch-reference-numbers/