They should have your Civil War ancestor's compiled service record, though it varies widely how much is in there. What regiment did your ancestor serve in? Depending on the state, we might be able to get it for free for you from Fold3.I have an ancestor who died at Andersonville, so there would be no records. Would the National Archives have other files on him?
Also, can I military files of my grandfather (WWII) there also?
Thanks, I just now am looking into this so apologies for basic questions.