Thank you everyone for the replies and information! And thank you to Bruce for directing me to the forum. I agree it's a real shame that this blade is such bad shape, especially now that you've given me a rough idea of its age. Since I'm not in it for very much I'll add it to my collection of wartime Japanese items.
Being that the whole piece is a bit of a Frankenstein is it possible that it was assembled as souvenir for occupying US forces?
The cover on the saya really has me stumped. I'm assuming it doesn't match up with the style of the "combat cover" we see on Type 95 and Type 98 swords? Someone on another forum suggested it was made from the outer casing of a firehose but I don't agree with that based on how tightly stitched and well fitting it is. If I'm feeling brave I may slip the cover off to get a better look at the saya.