The American Battlefield Protection Program, National Park Service, where
I worked before retirement, has supported archaeological study at various
Civil War battlefields.  There is also a new book out, "Look to the
Earth: Historical Archaeology and the American Civil War" (University of
Tennessee Press), that includes some essays on battlefield archaeology.
Additionally, you can find various published archaeology studies on
archaeology at battlefields from the many American wars.  Yes, a great
deal of battlefield archaeology has occurred.
 
 
Dale E. Floyd