You're right, there isn't much information on the web about those vises. My notes show a vise with
"Bay Vise & Tool Saginaw 12 Mich" castings that looks the same as the
"Superior Tool Co" vise. Although, neither one of these companies show up in any vise mfg. directories, there was a very small company,
"Webster Vise Works" out of very nearby
Bay City, MI that was producing vises in the late 1890's, which would've been circa correct for that style of vise.
You know I love vise puzzles, but this one is going to take some blind luck or a hard investigative effort to solve. I'd rather be lucky than good any day.