Crack,
I have heard similar things about the Kanji markings. I was hoping that it would give me an idea on what unit... and therefore what location the rifle came from during WWII. However, I am told that this was not documented... and that the Kanji are nearly meaningless.
If you are thinking it was a "bring back"... are you thinking Korea or Vietnam?
Looking at the wood, I don't know if you could consider it true Japaneseicon "Kanji" markings. Looks like markings from the Chinese "National Guard" type outfit.
Regardless, I think you have a cool looking rifle there!