For purposes of the Library of Congress, other than for public distribution, the Secretary of the Treasury and the United States Postal Service are authorized, upon the request of the Librarian of Congress, to forward to the Library of Congress fifty copies, or as many fewer thereof as are available, of all foreign prints determined to be prohibited entry under the provisions of section
1305 of title
19 and of all foreign prints excluded from the mails under authority of section
1717 of title
18.
Notwithstanding the provisions of section
1305 of title
19 and of section
1717 of title
18, the Secretary of the Treasury is authorized to permit the entry and the United States Postal Service is authorized to permit the transmittal in the mails of foreign prints imported for governmental purposes by authority or for the use of the United States or for the use of the Library of Congress.