19 C.F.R. § 134.51 : Customs Duties — U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY — COUNTRY OF ORIGIN MARKING — ARTICLES FOUND NOT LEGALLY MARKED — Procedure when importation found not legally marked

(a) Notice to mark or redeliver. When articles or containers are found upon examination not to be legally marked, the port director shall notify the importer on Customs Form 4647 to arrange with the port director's office to properly mark the article or containers, or to return all released articles to Customs custody for marking, exportation, or destruction.
(b) Identification of articles. When an imported article which is not legally marked is to be exported, destroyed, or marked under Customs supervision, the identity of the imported article shall be established to the satisfaction of the port director.
(c) Supervision. Verification of marking, exportation, or destruction of articles found not to be legally marked shall be at the expense of the importer and shall be performed under Customs supervision unless the port director accepts a certificate of marking as provided for in §134.52 in lieu of marking under Customs supervision.

19 C.F.R. § 134.51