I don't recognize the logo on the triangular insert, but if you look up "Cinelli 1r stem pantographed" it's fairly obvious that many brands - particularly Italian - used these stems and had custom pantographing done, and many of them had the Cinelli letttering as seen here. These were highly customized back in the day like all other pantographed parts. There's no good reason to assume this is a "stock" appearance.

-Gregory