The gearography site also shows she plays the guitar on Becuz:
http://www.sonicyouth.com/mustang/eq/gearsets.html
scroll down to 01/16/96, and click on "guitar" in the Kim column. It will open this page
http://www.sonicyouth.com/mustang/eq/gtr49.html
and also:
http://www.sonicyouth.com/mustang/sy/song125.html
and here are the tabs:
http://www.sonicyouth.com/mustang/tab/becuz.txt (which I can't really understand, except that I guess she only plays two of the strings)
but yeah, when you hear the song it does sound like she's playing bass. Here's a video, of the coda where you can see how she plays the notes, it looks she's playing only the strings for the high notes, or where the high notes should normally be in regular tuning (the bottom ones, hey I don't know how else to explain this):
https://www.youtube.com/watch?v=G48K...youtu.be&t=255
let's just conclude that she's playing bass on a regular guitar
