My understnading is that the UDC produced these medals for confederate service and all were awarded post war. Dates a little inconsistent but at least post 1898 which accounts somewhat for the rarity of reciepient, they were dying off!

Check the UDC homesite out or here is the scoop from Atlanta Chapter.
http://www.rootsweb.ancestry.com/~txvhdudc/southerncross.html

John R