43 C.F.R. § 30.123
Will the judge determine matters of status and nationality?
(a) The judge in a probate proceeding will determine:
(1) If relevant, the status of eligible heirs or devisees as Indians;
(2) If relevant, the nationality or citizenship of eligible heirs or devisees; and
(3) Whether any of the Indian heirs or devisees with U.S. citizenship are individuals for whom the supervision and trusteeship of the United States has been terminated.
(b) A judge may make determinations under this section in a current probate proceeding or in a completed probate case after a reopening without regard to a time limit.