Pics would help. If the stock is indeed laminated and original to the rifle, it would have been added during a post-war Russian rebuild, so no, it's not a finn capture unless someone recently added the stock set.
Very unusual for a 1931 era rifle to have anything "ground" on the receiver... unless it's a converted dragoon. They have what looks like grinding on the barrel shank, but it's actually a mill mark to make room for the old Konovalov dragoon sight which were mostly replaced in the 1940's onward.
The mismatched bolt hurts value considerably. Is it import marked? If import marked and mismatched, it's at best a $150 rifle. If not import marked, $175 or so. Had it been matching, laminate, and import marked it's about a $250 rifle. $275 if matching, laminate, and not import marked.
Confused yet?