Thanks a million for the reply Bruce and Geraint. I suppose I use samurai blade in a generic catch all term.
the sword belongs to a friend of mine in work and I've taken off the Tsuka to inspect the tang myself. I was thinking, could the blade itself be of an older vintage and refitted with Shin gunto Tsuka and tsuba hence the two hole. They don't appear to be drilled but appear to be forge punched as both holes are irregular in shape