@Emperor Tippy actually based on precedent from a case involving the Tlingit in Alaska, the ruling will probably say "actually, it
should be a reservation, and would be if you brought this suit in 1916, but because of laches, it isn't a reservation anymore because you waited too long to bring the suit." I am fairly confident their solution will be to just hold that laches applies and so the tribes waited too long to bring the matter before the courts.
On the other hand, in Oklahoma there is a lot of land which is owned by the tribes, but is not reservation land. Because this land being under state authority is an active, continuing state of harm, if they do use laches as the justification for refusing to recognise that eastern Oklahoma is tribal reservation land, the tribes could then renew a suit arguing specifically that land they own in Oklahoma which is not currently classified as part of a reservation
is part of a reservation, and laches doesn't apply because there is continued harm (having to pay state taxes on it), and they might subsequently win that case.