[Montana Bearbait]

I've seen a 42 Tula, that had the "CH" mark that I also thought was undrilled.
Once I looked at some (for lack of a better term) "speckles" in the metal right where the holes would be drilled for a PU mount I concluded that it had indeed be drillled, then later welded up later at refurb.
I needed good light and a magnifing glass to see it, the rework was so good.
So you might want to take a closer look.
Is the bore in good shape? Perhaps the "1" means it was top notch?

 

[Montana Bearbait]

Did the rifle you mentioned not show bolt holes/ends on the inside of the receiver? Tula, unlike Izhevsk, used blind holes for locator pins, but they used through holes for the mounting bolts.[/QUOTE]Sorry for the delay, lost track of the thread.On the outside of the reciever back by the slot for the stripper clip, there was a small verticle dimple in the metal, as though the weld had been sanded smooth a bit too deep.The inside of the reciever the holes had been welded shut too. The metal was slightly discolored and there were "micro-pits" like little gas bubbles in the metal on the bolt race.One, back by the slot for the stripper clip, and the other area was up front around the angled "bullet ramp".It was so well done that if one did not know what the "CH" above the Tula star meant, you'd never know that it wasn't an ordinary refurbed Mosin.Hope I answered your question.