Yes, you are referring to page 45 of Sasano's golden book.
The Bonham's tsuba is "ubu" and although it is extremely hard to judge from their low-resolution pics, I would say it looks like a later piece. I do not like the round, thick rim, and I do not like its size. If it were an ubu early Muromachi katchushi tsuba, the price would easily reach $$,$$$. If the price goes that high, I might be wrong. Japanese collectors would fight for such a piece, I presume. I suppose it is a 19th c. revival piece.