The censuses show a John C. Dickenson/Dickinson of that age in Marshall 1880-1900, but no Dickerson that matches. He may be this man:

http://www.sos.mo.gov/TIF2PDFConsumer/DispPDF.aspx?fTiff=/archives/AdjutantGeneral/Civil_War/ServiceCards/s729/3170.tif&Fln=S396112.pdf