Generally all L versions of the 1000 series (L versions simply have an "L" after the reference number e.g 980.013L) featured push-in crowns. Generally all models before or after featured screw down crowns, the Pre-L versions (Heuer-only at this point) were unsigned screwdown crowns and Post-L (all Tag at this point) feature the screwdown Tag shield crowns. If shopping.......L versions are the least desirable (in my mind) due to:
a. poor choice of crowns for dive watches
b. finicky movements (963 esa series)
c. transitional period so anything goes and some sellers mismatch or swap parts so its really hard to tell if your watch has been fettled with or if its original.
99.999% of the push-in crowns leak by now and if swimming, change your crown and tube. The push-in gaskets are not replaceable in our experience to the point of achieving anywhere near the rated water resistance.
The OTD table referenced above and the Calibre11 pages on the 1000s just about perfectly cover the changes throughout the years. The OTD table is all pre-Tag but the styles still matched up with the Tag versions produced after the merger. The catalogs on Calibre11 will fill in any gaps and show the variety of styles offered during the Tag period. By the time the "B", "N", and "D" Tag versions came around they were largely all the same with the exception of color combos.
If you have any other questions feel free to message us on the website.
Thanks,
Justin B
www.Tag1000Diver.com
