Are you talking about the parts manual or the service manual? The MC16/18/21 manual contains the starting frame number for each model (16/18/21). does not provide any seq numbers.

MC16 = MC16-1000001 (1987)
MC18 = MC18-1000020~ (1988)
MC18 = MC18-1100001~ (1989)
MC21 = MC21-100000~ (1990-1993)

Only information provided in the service manual.

If you are looking for an MC21 Service manual, they are available in English here. This includes the MC16, 18 and 21 models, layout is exactly like the original Japanese manual with FULL translation into english.

If you are looking for an original manual to provide as proof of Frame number to your government, check with Moriwaki man, he can get you a copy from Japan.