FWIW, "26 acoustic guitar (steel)" is the GM instrument definition for instrument patch #26, so that's where the definition comes from. PGM are just saying it's a steel-strung acoustic guitar, nothing more than that. They may/could/should put more detail in the notes.
From the old DOS midi days, now it's "Look Ma no Midi" real instruments need real names so when you search it will show all the same instrument that will match in tone.
I do often wonder just how long some of the stuff is BiaB actually goes back. Certainly some of the companion programs look like VGA or Win3.1, presumably in some kind of wrappper.
"26 Acoustic Guitar", even with the musician's name still doesn't really tell nearly as much as it should. There definitely should(*) be infomation there somewhere about the make/model of guitar.
(*) "Should", unfortunately means virtually nothing. Implementors can simply choose to ignore it.