I ran across the above article about six months ago and accepted it as just another "authenticity" paen (or pain ??). A similar, much longer, more informative and less sarcastically toned piece appeared in one of the "Buckskinner" journals a number of years ago.

I second Kim C's inclusion of guitars. There is at least one Civil War photo of a soldier "band" which includes guitar, fiddle, banjo, bones and triangle.

I've also seen a photo of a civilian African-American group c. 1860 that includes two fiddles, a banjo, and a small bodied guitar.

What I haven't seen a photo of, although they were supposedly common, is someone playing a harmonica. (See other thread, Civil War Harmonicas)