I just realized that the words and sheet music are in Irwin Silber's Songs of the Civil War (New York: Columbia U. Press, 1960), p. 363 & 364 (it's the last song in the book). The book should be available in libraries or via interlibrary loan.

Yes, the song is credited therein to Irving Gordon with a copyright date of 1951 by Shapiro, Bernstein & Co. You might want to look into what you have to do if you want to perform the song for profit....