Upon the determination by the United States Treasury Department of an overpayment of income tax by a married couple filing  a joint federal income tax return, one of whom has died since the filing of such return or where a joint federal income tax return is filed on behalf of a husband and wife, one of whom has died prior to the filing of the return, any refund of the tax by reason of such overpayment, if not in excess of five hundred dollars ($500.00), shall be the sole and separate property of the surviving spouse. In the event that both spouses are dead at the time such overpayment is determined, such refund, if not in excess of five hundred dollars ($500.00), shall be the sole and separate property of the estate of the spouse who died last and may be paid directly by the Treasury Department to the executor or administrator of such estate, or to the person entitled to the possession of the assets of a small estate pursuant to the provisions of Article 25 of this Chapter. (1955, c. 720; 1957, c. 986; 1973, c. 1329, s. 3.)