Deplaylady,
Nice Minnesota B. This is a Davis Model G rather than an M-E, which came from an article in Ismac's which is about 10 years old. I don't think there's anything more recent or better to replace it (the article) with but 75% is good. The Davis models are on the yellow sheet which came from an Excelsior SM supply catalog. I don't think the feller writing the article in Ismacs had access to this.
http://needlebar.org/nbwiki/index.php/Davis
"B"'s were made from 1899(Burdick) or so till around 1910. Yours is about in the middle of that, 1905. I see you were able to pry it away from your daughter
Jon