Another thing to consider is that, even thou the sword got through (unlikely), the relatives of the former sword owner might not have the license.
It is illegal to own a "real sword" (old or new) without a license in Japan.
Also no bayonets, they need to be cut few inches above from the "neck" in order to own them.
There was a live crime scene (can' t remember which) of a man holding a Japanese war time bayonet and broke into someone' s apartment and stabbed the person to death in front of Japanese media (80's ). After this incident, no full bayonets are allowed in Japan, unless they are nonmagnetic (from what I remember).