I believe Ken Sanderson of the MTP once told me that there was an Edison
recording, supposedly of MT reading from Huck Finn, that was actually by
someone else. I have forgotten the details, but some scholarship had been
done on this actual recording and it proved to be by an actor of the day
and not Twain. I believe current scholarship has established that all
recordings by the man himself were probably destroyed by fire. I keep my
eyes open however, as you never know what will be found "under the cat"!
Cheers,

Rhio H. Barnhart
University of California, Davis, CA