I am not sure which registry you are referring to exact. I haven't actually researched the Mississippi grave registration program to know the complete facts, but it is my understanding that it was a WPA program in the 1930s to locate and register all Confederate graves. The only Miss. Registers I know of are, I believe her name is Betty Wiltshire, and the online site at http://mscgr.homestead.com/index.html. I know there are errors in the online site, but Mr. Don McCaskill asks for corrections. Send him an email with a copy of your documents as proof asks him to add or correct the information.
I have started a list of my own, this is generally Miss. soldiers who found in the out of the way places and not listed anywhere else. If you know of such a man please post it to this board and I will record it.