§ 229-g. Marking watch cases sterling or sterling silver. Any person, firm, corporation or association who makes or sells, or offers to sell or dispose of or has in his or its possession with intent to sell or dispose of, any article of merchandise comprised of works or movements and a case or covering applied or attached thereto, wholly or partially concealing said works or movements marked, stamped or branded with the words "sterling" or "sterling silver," unless said case or covering shall contain not less than nine hundred and twenty-five one-thousandths parts of pure silver, is guilty of a misdemeanor.