The more I listen to "Last Kind Words" and other tracks by Geeshie Wiley, the more convinced I am that the guitar is a 12-string. The B string has that phase-y sound that 12-strings have, and the bass strings sound like they have octave strings. Same with the playing on Elvie Thomas' "Motherless Child Blues".
On "Skinny Mama Blues", it sounds like the treble E string isn't doubled as a 12-string would be, so I'm not sure about that one. Maybe it's an 11-string?
I know that the conventional wisdom is that "Pick Poor Robin Clean" is a guitar duet, but I think it could be just one strong player using a 12-string (which makes sense, in that one of them claims to be playing blues about cock robin, while the other asks to hear it).
Side note: what the devil does Geeshie call Elvie Thomas in the intro to "Pick Poor Robin"? The exchange is something like:
"Hello there, Geeshie"
"Hello there, sluh"....
