If you have a Muncie with a similar character after the date, can get a photograph of it and KNOW whether it's an M20, M21, or M22, please pass it along. 1968. 1968 Muncie transmission tag #3924706. Date stamped P8P27 for Muncie, September 27, 1967 and partial VIN of 18K116891. Reported to be M21 but cannot fd tag number to verify.