just a note, a pre-1930 date does NOT automatically mean "ex-Dragoon." In fact few Dragoons were so converted, and any that were have long been scarfed up by collectors.
Most "91/30's" with pre-1930 dates are actually better called "Transition" rifles, and were actually just older M91s converted to 91/30 specs after 1930.
I have owned about 10 of them, still own 2, 0ne dated 1920 and another dated 1929. I wish I still had the sweet 1928 Tula somebody made me a good offer on...
and none were actually an "Ex-Dragoon," although I WISHED each were when I bought them....
But "Transitions" are neat in their own way, abnd besides a lot of Czarist markings from the pre-91/30 days left on many of them, they all differ slightly in the conversion, many apparently done as "one offs" at various arsenals and shops, and not mass produced.
But all of the differences you find on any other Mosin Nagant, such as pre-1936, pre-war, wartime, post war rearsenaled, etc, can be found even on these "new"ones, which makes them just as neat to own and research and shoot as the "old" ones.