Mr. Curtis- This same question is being asked by a Connie Curtis on the message board at http://www.civilwarbuff.com/ubb/cgi-bin/ultimatebb.cgi

You'll seem to be related:-)
In answer to your query- the Federal Graves at Helena were moved to the National Cemetary in Memphis. However, the names of your ancestors do not appear on the list of known burials. It should be noted that many men are buried as unknowns and it is probably that the identification of the remains was misplaced or lost before the burials were moved. Many CW graves were initally poorly marked and time and weather frequently obliterated those. Good Luck