(b) Possibility of additional distributees.--If the existence of a person or persons would affect the distribution of an estate but there is no proof that such a person ever existed, and the court is satisfied that all reasonable steps have been taken to determine whether such a person existed, the court may award distribution of the estate to those who would be entitled if no such person existed, with or without refunding bonds. Any such bond shall be without security, shall be in such form and amount as the court directs, shall be executed by each distributee and filed with the clerk, and shall provide that if, within seven years or any shorter period fixed by the court, it is later established that there is an additional person or persons entitled to share in the distribution of the estate, the distributee upon demand will return such portion or all of the property received by him as the court may direct or, if it has been disposed of, will make such restitution as the court deems equitable. In the case of distribution under this subsection to the Commonwealth as intestate heir, in lieu of bond, payment shall be as provided in subsection (a).