After reading the extensive history of "Blonde On Blonde" mixes and issues from hyperlink Chris provides above, I realize that things are not nearly as simple as I had assumed when I wrote the above post a half-hour or so ago.
I bought the album as soon as it became available, probably at a discount store, so I undoubtedly had the original US mono mix described in the article as the standard or best. And there were several early CD versions, none of them considered very good at all.