Section 304.5 - Marking requirements for imitation political items(a) An imitation political 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 with the calendar year in which such item was manufactured.(b) The calendar year shall be marked upon the item legibly, conspicuously and nondeceptively, and in accordance with the further requirements of these regulations.(1) The calendar year shall appear in arabic numerals, shall be based upon the Gregorian calendar and shall consist of four digits.(2) The calendar year 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 political item of incusable material shall be incused with the calendar year in sans-serif numerals. Each numeral shall have a vertical dimension of not less than two millimeters (2.0 mm) and a minimum depth of three-tenths of one millimeter (0.3 mm) or one-half ( 1/2 ) the thickness of the reproduction, whichever is the lesser. The minimum total horizontal dimension for the four numerals composing the calendar year shall be six millimeters (6.0 mm).(4) An imitation political button, poster, literature, sticker, or advertisement composed of nonincusable material shall be imprinted with the calendar year in sans-serif numerals. Each numeral shall have a vertical dimension of not less than two millimeters (2.0 mm). The minimum total horizontal dimension of the four numerals composing the calendar year shall be six millimeters (6.0 mm).