I have no idea if the man Leeper wanted was Robert J. Tucker or not either.
As to his service with Elliott, the records show that he joined the 5th MO Cav in the summer of 1862, transferred to Co A, Elliott's Battalion in the fall of that year, and remained with that outfit until the end of the war. He was promoted to captain of Co A of that battalion about May 4, 1864, and remained with it after it became the 9th MO Cav during the Price Raid. He was age 23 at the time of enlistment, and was from Lafayette County, MO, according to the muster rolls.