Tom,
Yes, I found it strange that the name on the bag has the name Tashiro Masao, but on the box it says Matsuoka, and the rail card has the name Nakayama Toshiro. It would be interesting to investigate those names, and if I'm lucky, I could find out who this sword originally belonged to.
On a side note, despite this sword being a showato and not a true gendaito or nihonto, I would eventually like to have it polished. It has a lot of sentimental value, and I would like to pass it down in the family. Are there any good sword polishers that would entertain the idea of polishing a showato blade?