Any person may import at any Customs Service port designated for such purpose, any article (other than scrimshaw, defined in 16 U.S.C 1539(f)(1)(B) and 50 CFR 217.12 as any art form that involves the etching or engraving of designs upon, or the carving of figures, patterns, or designs from, any bone or tooth of any marine mammal of the order Cetacea) that is at least 100 years old, is composed in whole or in part of any endangered or threatened species listed under § 17.11 or § 17.12 of this subchapter, and has not been repaired or modified with any part of any endangered or threatened species on or after December 28, 1973.