Other departments, agencies, and other entities of the United States Government shall cooperate with the Office of the Historian by providing full and complete access to the records pertinent to United States foreign policy decisions and actions and by providing copies of selected records in accordance with the procedures developed under section 4353 of this title, except that no access to any record, and no provision of any copy of a record, shall be required in the case of any record that was prepared less than 20 years before the date of a request for such access or copy made by the Office of the Historian.