Before the expiration of the period ending 18 months after the appointment of the Director under section 4512 of this title, any rules and regulations promulgated before October 28, 1992, by the Secretary pursuant to the Federal National Mortgage Association Charter Act [12 U.S.C. 1716 et seq.] or the Federal Home Loan Mortgage Corporation Act [12 U.S.C. 1451 et seq.] shall remain in effect unless modified, terminated, superseded, or revoked by operation of law or in accordance with law. Such rules and regulations shall terminate, effective upon the expiration of such period.