Library Bureau Sole Makers Table

History buffs, furniture fanatics, antiques wizards - help me figure out exactly what I have here!

So far I’ve figured out that the Library Bureau Sole Makers company, founded by Melville Dewey (of the Dewey Decimal System!), made furniture and filing systems for libraries from 1881 to the 1950s.

I’ve found some old company catalogs online, but nothing showing a piece like this. It’s solid wood (maybe quatersawn oak?). The metal hardware looks like brass - label holders, and a channel that possibly held a cover of some kind? There are rubber stoppers on either end of both tracks.

It comes apart into 3 pieces - the top rail comes off (as seen in the picture), and the slatted top separates from the legs.

Measurements are 48” tall at the back, 62” wide, and 24” deep.

I would love to know the history of this piece, and what it’s original function was!