Section 483(b) of Pub. L. 98–181 provided that: “Any purchase or commitment to purchase any mortgage pursuant to section 305 or 313 of the Federal National Mortgage Association Charter Act [former sections 1720 and 1723e of this title] made before the date of the enactment of this Act [Nov. 30, 1983], and the servicing and disposition of any such mortgage, shall continue to be governed by the provisions of such sections as they existed immediately before the effective date of this section [Nov. 30, 1983].”