patrickwall, the gun you're looking at appears to have been built in the early 1960's. In Wieland's
Spanish Best, Ugartechea's S/N's show 1960: 39,990 and jumps to 1965: 50,702.
Lloyd3, your gun 57 03 12 97 was actually the 12th gun built in 1997. 57 is the maker's ID and the 03 signifies it's a shotgun.
Larry, it appears that you're correct as usual
an Arrieta I have that was built in 1996 bares both codes and another Arrieta I have, built in 2007, only has the build year as part of the S/N and is sans the date code on the barrel flats.
