what is the meaning of 3YWLO stamped on a cross neckless?

I googled it and it seems like it’s just some kind of production code.

3YWLO. This is the 5 digit code which was assigned to GI Jewelry by the U.S. Government as an identifier of who they are and the religious jewelry that they make.

“CAGE” Code: 3YWLO. This is the 5 digit code which was assigned to GI Jewelry by the U.S. Government as an identifier of who they are made for.

It’s a 5 digit US government identification code for military-issued jewelry, to show what religious affiliation the GI was.
http://www.themagicwand.co.uk/gi_jewellery.htm

U.S.A. G.I. issue Buddhist pendent made in stainless steel 303 regulation size and specification size worn on dog tags , identified Buddhist