My father had mentioned star gauged barrels as something special as far as accuracy. After not seeing anything for a while about star gauging, I got to thinking that it might have been a first article mark after refreshing all the tools on a production line.
If your article is correct and it involved special work done for match rifles that is a different story. I gotta say stamping the end of the barrel is not something I would do. The metal displaced would affect the bore. I had a machine installer tap a table gib out with a screw driver made a similar mark, ran the table back and forth a couple of times and the displaced metal made a gouge in the table way. Scrapped a $25,000 machine that never made a single part after the CNC installation.