Does anyone know if the 320 line of shotguns have proofed barrels, and if so, are they proofed by the maker or by Savage? My 12 gauge Security has what might be a proof mark on the barrel and it's located about a half an inch left of the words "Mfg by ..." I can't quite make it out even with a magnifying glass, but it is obviously stamped on the barrel and is unlike all the other evenly cut and spaced lettering.