Ted,
You might just have hit on the reason. The scoring was one line, at about 10 o'clock and looked to the naked eye to be relatively deep. I pondered on how, the scoring didn't look wide enough to have been the possible single steel pellet that got outside of a wad. Had there been any reason at all, one would have thought it was machined into the barrel. As I wasn't gun shopping I had no tools to check it out properly, but I'm confident that neither the stock nor the bbls. had been cut. Overall a nice shooter, but alas.........
Steve