The Creek nation began disenrolling freedmen tribal members in 1979. Litigation by the Descendants of Freedmen Association in the Creek nation tribal court on behalf of Creek freedmen descendants was not successful.
A link to the 1866 Creek treaty is below:
http://digital.library.okstate.edu/kappler/vol2/treaties/cre0931.htm
Earlier cases dealing with Creek freedmen including Sango V Willig http://www.oscn.net/applications/oscn/deliverdocument.asp?id=53942&hits=3989+3987+3925+3882+2250+2225+2212+2195+2081+2038+1913+1909+1891+1889+1824+1781+317+292+279+262+156+113+3+1+