I have a magazine that has an article about it.

it is called Acoustic guitar may 1999

they say it was a Martin 2 1/2 -17
and that he got it shortly after the outbreak of
the Civil war in 1861

there is a little more, but I have to go get ready
to catch a plane to Europe. I'm hoping to find
some Twain info while there :)

See you all in a little over 2 weeks :)

Jules