except as provided in subsection (b), any civilian service performed before
January 1, 1989 (other than service under paragraph (1) or (2)), which, but for the amendment made by section 414 of the Federal Employees’ Retirement System Act of 1986, would be creditable under part I (determined without regard to any deposit or redeposit requirement under such part, subchapter III of chapter 83 of title 5 (the Civil Service Retirement System), or title II of the Central Intelligence Agency Retirement Act (
50 U.S.C. 2011 et seq.), any requirement that the individual become subject to such part, subchapter, or title after performing the service involved, or any requirement that the individual give notice in writing to the official by whom such individual is paid of such individual’s desire to become subject to such part, subchapter, or title).