Mine is stamped, but well and neatly stamped. "S" in a circle. It was a clean barrel - didn't appear to be any kind of alteration to a military barrel. I don't know what sort of odd-ball, small lot work Springfield or Winchester or even Savage would be willing to turn out - I expect it was pretty free and easy. I expect if you needed a hundred or so barrels in 30-06 (or other standard chamberings) you could get them on relatively short notice, especially in the 30's when people were selling their dental work to keep food on the table.
