(a) The order of final distribution shall be a conclusive determination as to the persons who are the successors in interest to that part of the estate of the decedent passing through the hands of the personal representative and as to the extent and character of their interests therein, subject only to the right of appeal and the right to reopen the order.
(b) The order shall not affect the rights of third parties acquired from or through a distributee, as against the distributee.