With several surviving examples, it would seem that Southern unpainted knockoffs of the standard U.S. haversack were not terribly uncommon and deserve some representation in the ranks.  Not your mainstream import junk, these are spot on copies of the original.  From the maker, L.D. Haning & Co.:

"One of the more exciting projects for me in a while. I had been thinking about this new product for quite some time. This CS haversack is based on one in Gettysburg National Militarty Park collection.  It is an unpainted cotton drill example that originally contained an inner liner as does our reproduction.  We worked closely with Family Heirloom Weavers and their vintage looms again for a cotton drill perfect for this reproduction.  The original liner was suspended by tinned plain buttons rather than paper backed as typically seen in federal production haversacks.  This haversack also contains a somewhat unique oblong bottom. It contains some machine stitching but predominately hand stitching including the leather and buckle closure. The body measures approximately 12 by 11 inches. A very sturdy useable design."

CS Haversack - The Final Campaign