Sir,
I may have the answer.
In Volume 6 Page 237 of the Virginia Cemetery Series, Men in Gray Interments, there is a John McNath, Co. D 12th GA, date 5/19/1862, listed at Thornrose Cemetery. I think this is John McMath as I can't find any Mcnaths, John or otherwise, on any roster for the 12th.
Also in same volume, the author states that there are only about existing individual Headstones in the Confederate Section, out of approximately 800 burials there. If true, How did these lists come to be? Are the names of the others inscribed on some sort of memorial? Any Information would be greatly appreciated.

YOS,
George McMath