Kathleen Mavourneen was indeed published prior to th War Between the States. I do recall the tenor's rendition in the movie. I also recall a short bit with Joe Ayers performing a tune- what one I don't recall. I was on the set myself where we spent some time together. My pards and I have reenacted CW for 20 years or so. At some point we recognized that Bluegrass and Old Time was not at all appropriate for the hobby and began avidly researching and then performing in a truely period fashion. This has lead to fasinating insight to the much maligned topic of Blackface Minstrelsy- the fusion that was America's first indiginous musical form (sorry, it wasn't Jazz) and which spawned Old Time & Bluegrass, much of AmerFolk, tapdance and Vaudeville, and maybe even TV sitcoms! You can check us out at http://www.monumental.com/sanfords/serenade.html