I have a new old stock Michigan AJ-530 for the Martin 200s. It is bronze, about 6.5 inches in diameter, right hand rotation, likely for racing applications. Not sure what the pitch is. Comes in the original box, with a small pamphlet insert. Box is in nice shape, too. AsKing $100, postage in the U.S. included. Photos available upon request.
Email: csr112-n AT twcny DOT rr DOT com