McGuire is listed as present for duty throughout his term of service for which muster roll records have survived.
McGuire mustered out with the regiment on September 5, 1865 at Knoxville. He had never
been paid, owed $24.37 to the government for clothing in kind or money advanced, and was owed a $300 bounty.
McGuire died April 12, 1890 in Prairie City, Oregon and is buried there at Prairie City Cemetery. His wife applied for a widow's pension on April 12, 1890.
Due to confusion among descendants, McGuire is buried under a modern Confederate headstone that erroneously records his service with the 6th Tennessee Cavalry, CSA.<ref>Attempts to contact descendants to correct this error have gone unanswered.</ref>
Both men were serving in opposite armies at the same time and it thus impossible that James K. McGuire had served as a Confederate soldier.<ref>The other James McGuire enlisted on September 25, 1863 as a corporal in Company E, 6th Tennessee Cavalry, CSA, at Bowling Green, Kentucky. His residence was given as Columbia, Tennessee and he was paroled at Charlotte, North Carolina on May 3, 1865.</ref>