It's condition is remarkable, I'll agree. That leads me to think it was probably used in Japan, possibly by a guard at a POW camp or some similar duty. It's a little dinged up, but that could've occured when the rifles were piled up together at the end of the war.
I've cleaned the rifle a few times, conditioning the wood and oiling the metal. However, if you take another look at the bayonet, you'll see some "weathering" that I've not been able to get rid of. I assume this is a natural oxidation of the steel but I can't rule out blood stains. I'm inclined to locate a scientific community to donate the bayonet to, just to find out if there's any DNA samples they might be able to obtain from it.
Next stop: National Geographic (I can dream, can't I?)
EDIT: As a side note, the weapon, with bayonet mounted, is heavy. It's difficult to imagine a Japanese soldier trudging along in the jungle, carrying this rifle. It puts the faith in their Emperor/God ideology into perspective a little, as there was no way to honorably serve their country than by hardship and death in battle with the enemy. That's the only thing that keeps me from utilizing more drastic measures in cleaning the bayonet. If there's blood on it, I don't dare to rid of it.
Another side-note, the rife fires 7.7mm rounds, which are VERY expensive. If it was even fired during WWII, it would've been the last time, since my father never fired it. I assume it's safe to shoot with it (if I fork over the money for the compatible ammo) but should I risk it?
I'll post some more pictures with the elevation/windage sights up...I completely ignored that part of the weapon.