The seller of this guitar never mentioned a word about the writing (autograph?) on it when posting it for sale on-line.  He reduced the price because of it.  This was not sold to make more money because of the signature.  The seller seemed to be unaware as to who "Jim Morrison" may have been.  The guitar itself was a FIRST YEAR ISSUE of C. F. Martin & Co.'s Sigma line.   It was a comparatively expensive guitar in 1970.  It is difficult to believe that a guitarist (most of us worship the…