M date coded parts

[70camfan]

I thought L was the code for December made parts, if so, what does an M stand for in date coded parts?
Thanks,
Bud

 

[70L34]

Date codes for some parts do not use the letter"I" in order to avoid confusion with the number "1". Then, Sept.=J,Oct.=K,Nov.=L,Dec.=M.
Dale

 

[Gary S]

What parts?
GM commonly skipped the letter "I" to avoid confusion with the number "1", so on a distributor, "M" would be December.
On transmissions, it was common to skip even more letters so "M" often would be August.