Maybe they COULD have been notched..they still were in '61 from what I've researched. Excellent question..I'm sure someone has a set to tell you for sure.
I got a great set from a eBay seller that has new old stock blanks, and he has THIS:
Dated '64, to where he claims may have been the first UN-notched..
He also has a '61 set that is notched..
I'm not affiliated with the seller in anyway..I just wanted to share my findings..the font, strike depth..EVERYTHING is spot on perfect. I am very happy with them, and had set made for my gramps (USN '52-'56, Gator Navy LCVP coxswain)..he was even able to replicate the "errors" on the original notched tags! (upper case I used instead of 1 in SN#, spaced out 2 spaces on top line..) So at least we got '61 and '64 down..but that sure doesn't help with your years..dang it!
You could even put it on a 1945 dated chain if you so chose! (I did!) I had my tags redone on the '64 blanks..the stainless is very nice from then, duplicated my original tag format from early '90s..I wear them everyday.
('45 dated could have been still as new issue many years later..ESPECIALLY in the USN and USMC!!! Plus, I love the history!)
I had first got a real set of AWFUL tags..the tags were good themselves..but they weren't struck deep enough..like machine was 20 years past wore out..but stumbling across this seller fixed all of that for good.
Do you remember the exact format of your original tags?
Edited by KRIS FORD, 11 March 2018 - 10:40 AM.