'Conviction' includes a plea of nolo contendere to a felony.'Antique slot machine' means a coin operated, nonelectronic mechanical gambling device that pays off according to the matching of symbols on wheels spun by a handle and was manufactured in its entirety, except for identical replacement parts, prior to January 1, 1950.A person who knowingly owns, manufactures, transfers commercially, or possesses any device which he knows is designed for gambling purposes or anything which he knows is designed as a subassembly or essential part of such device is guilty of a misdemeanor of a high and aggravated nature.