Vintage Pre-Owned Cufflinks, Sterling & Lapis Lazuli marked "DaVinci"

Gorgeous Pre-Owned and gently loved and worn,.....circa 1960's ? Vintage Cufflinks marked "DaVinci" are also marked Sterling Silver on the back and the toggle post. There are numbers incised into the post as well, probably indicating a model #. They have oval cabachon stones of Lapis Lazuli, channel set into a variant color of blue lapis luzuli. Dark blue lapis stones are repeated in the toggle as a narrow marquise shape cabachon.