There's always the chance the rifle got to spend some of it's life in someplace like Israel, Netherlands, Belgium, Greece, Iran, Turkey, etc. Right after WWII, some of the re-building and re-structuring countries/states that didn't swing towards Russian influence adopted NATO trends such as ammo, rifles, and other equipment. Not all governments armed up strictly their armies. There were all sorts of forestry, police, guard, rail roads, and border security entities that were armed up in these countries. I remember reading where there were actually quite a lot of M1 Carbines issued to the German Forestry after the war. And quite a few Nazi marked Mausers ended up being present for the birth of Israel.
That stock looks way too fresh for me to believe it was issued to anybody, but the flaking black paint- I've seen that before on different rifles from different countries. In truth, there's just not much of a way to tell what that rifle has seen in it's prior life or where it's been.