The provisions of this or any other law to the contrary notwithstanding, any person who becomes director of the Office of Treasury and Fiscal Services, State School Superintendent, Commissioner of Insurance, Secretary of State, Attorney General, Commissioner of Labor, Commissioner of Agriculture, or Public Service Commissioner after April 1, 1964, shall become a member of the retirement system and shall not be eligible for the corresponding emeritus position, provided that any person holding any of these offices on April 1, 1964, shall not be prohibited from appointment to the corresponding emeritus position.