In any case, even if such a document existed, with Nigeria's independence in 1960 it ceased to be valid because all entities in Nigeria at the time partook through their elected representatives to discuss and agree on terms to be part of the new country.
For any case, even if such document dey, as Nigeria take get independence for 1960 e no go dey valid again bikos na evri entity for Nigeria dey take part wit di representative wey dem elect to take discuss and agree on top di new kontri.