New Question! Cameo , made in Italy

[Ohimesama]

I know the cameo is made in Italy, it's stamped 925, then stamped Italy, (and a sticker on the back says 'made in Italy - that was easy!) but next to it is another indent section with a 5 point star, the numbers 351 (or 361, hard to tell) and either NA or NO. I know it's the maker and region - but how can I tell who and where? Where do I find the information?