Perhaps because the whole story smells a bit funny, it gives place to legitimate speculations. A couple further details would make it appear more plausible.
The date and price mentioned may be realistic, but do lack support; that certainly not the sudden expertise of the Swiss Customs in the Nihonto universe.
They say they found an invoice; was it the one covering the sword purchase, and was it so detailed as mentioning such explicit elements; what for? Do you send your driver (and his daughter) transport a sword between countries, with such revealing document ? Why not sending no invoice or one describing a (replica) sword made in China (right, Ariel ?).
Definitely something doesn't square ... if i may
Maybe one of these days we hear further from the press on this, other than the initial 'breaking news' article.