I found him buried at Bellefontaine Cemetery in St. Louis
The stone is inscribed simply "Gen Chambers"
Find A Grave website states "CSA. He died fighting in S.E. Missouri."
Greg Biggs found an article in St. Louis Tri-Weekly Republican of April 6, 1864.
which stated he was a captain and killed in a skirmish with the 8th Mo. Cav. MSM.
A small flag taken from his body was displayed in Gen. Gray's HQ.
The resulting confusion I blame totally on Greg.