16 CFR § 304.6 - Marking requirements for imitation numismatic items.
(a) An imitation numismatic item which is manufactured in the United States, or imported into the United States for introduction into or distribution in commerce, shall be plainly and permanently marked “COPY”.
(b) The word “COPY” shall be marked upon the item legibly, conspicuously, and nondeceptively, and in accordance with the further requirements of these regulations.
(1) The word “COPY” shall appear in capital letters, in the English language.
(2) The word “COPY” shall be marked on either the obverse or the reverse surface of the item. It shall not be marked on the edge of the item.
(3) An imitation numismatic item of incusable material shall be incused with the word “COPY” in sans-serif letters having a vertical dimension of not less than two millimeters (2.0 mm) or not less than one-sixth of the diameter of the reproduction, and a minimum depth of three-tenths of one millimeter (0.3 mm) or to one-half ( 1/2) the thickness of the reproduction, whichever is the lesser. The minimum total horizontal dimension of the word “COPY” shall be six millimeters (6.0 mm) or not less than one-half of the diameter of the reproduction.
(4) An imitation numismatic item composed of nonincusable material shall be imprinted with the word “COPY” in sans-serif letters having a vertical dimension of not less than two millimeters (2.0 mm) or not less than one-sixth of the diameter of the reproduction. The minimum total horizontal dimension of the word “COPY” shall be six millimeters (6.0 mm) or not less than one-half of the diameter of the reproduction.