I have researched these men and George is correct in what he has stated. You can verify this by census records and also the CWS&S at http://www.itd.nps.gov/cwss/soldiers.cfm.
Those of us who have researched the 7th miss. also believe there may be more than one Samuel Slade in the Co. D, 7th Miss. If you will email me at gpthelastrebel@cableone.net, Mitch and I will try and help you sort out the information.
GP