WW2 Japanese sword with piece of paper found in the tang

[JKL]

I bought this Japanese sword at an antiques market in England a few years ago. It came with a piece of paper that was found in the Tang with what looks like Japanese writing on it, not sure if it is the signature of the maker?  Any ideas on value or age given your experience? Posting some pics below. Thanks! 

[Polaria]

My notes:

• Looks like shin gunto koshirae
• Saya is non-standard for shin gunto
• Fuchi is non-standard and looks cheap
• Black same and black paint on mekugi head look suspect
• Tsuka ito looks off

Without seeing the tsuba, seppa and kabuto-gane in detail it's hard to say, but my guess is that this might be pieced together from authentic and after-war parts. Have you disassembled the sword yet?