Fox Collectors

Hey guys,
I have a 16g Sterlingworth #364195 with a 3 weight barrel stamp. I'm curious as to why some Sterlingworths were stamped with the bbl weight but many, ( most ? ), we're not. Three others I've owned we're not stamped.
Best for the new year, Jim

It seems that at least as often as not, the weight stamps for the rough tubes got struck off during the processes of building the completed set of barrels.