Larry,
As 8Bore says, they were likely struck off. The number, if present, is somewhat helpful if you're describing or reading about a gun for sale..."the 30" 12ga barrels are stamped #4"....."ooooh, that's gonna be a light gun." It's at best just indicative of where the gun will fall in the range of weights for a 30" 12. But it's sort of analogous to "the chokes are IC/Mod." If we know the weight of that 30" 12ga or the bore dims, we have the real story in spite of what the markings are.
If I were looking to build the heaviest 12ga I could, I'd be interested in checking out any with #1 barrels. But I'd much rather have the exact weight of the barrels in ounces.
The majority of 16ga SW's I've examined are 28" marked #3 (medium-light) or not at all. Seems reasonable that would be by design for a mass-produced gun with no option for specifying gun weight. They come in at 6 1/8 - 6 3/8 lbs. Average gun = equals average barrel weight. If you ordered a graded heavy 30" 16ga choked F/F, you likely specified "7+ lbs", not #1 barrels.
