" I checked the online National Archives, but neither has a record; why would their info be missing? " I don't understand what you were looking for. These men died as civilians long after their service was completed. The only thing military about their deaths was the issuance of a veteran's head stone. The National Archives had their personell files, but, millions of Army files were destroyed in a fire in 1973.The only way to find out if particular files exist is to make an application to obtain them. The instructions to do that are listed on NARA's web site. There is no information shown about anyone in particular. The only way to get particulars about anyone's tour of duty is to get their personall file, separation paper or whatever records might show in any dealings they had with the Veteran's Administration.