Transmission Serial Numbers

Hello All,

I am in the process of building a 1973 850 Commando with matching frame, engine and trans numbers (well not quite an exact match on the trans number). The trans number has a "C" after the serial number.

I've owned 5 Commandos during the past 12 years ('68, '72 Combat, '73 and two '74's). All with matching numbers but only the '73 has this "C" on the trans. Does anyone know what the "C" refers to?

I have a 1970 Roadster and all numbers matching and I have an "E" after my ser# on my transmission. I was wondering if it designates where it was made, or year or model. I just found another post on this site with an owner who has 1968 transmission with a "C" after the transmission ser# as well.