The recess was found not to be needed and was discarded in later lenses. Engraving on middle chrome lens barrel. PEND, possibly due to lack of space on the thin chrome barrel. It was the combination of these features which made TICK mark lenses unique. It is also possible that some late TICK lenses are transitional and do not have ALL of the above features.
More research needs to be done.
TICK Mark Lens Production TICK Mark Production figures has long been a problem to Nikon F Collectors, and still is . If you have a TICK Mark lens, please email me with the serial number and details of your lens . Many details are still not known. Information on this page will change as better information comes to light. While I helped fill in a few blanks, most of the production figure research was done by Swiss Nikon Collector Richard de Stoutz.