1967 Barracuda fastback fender tag deciphering

M2 is on my fender tag as well.
All options/codes accounted for, and it only has a few.
I have the IBM build card, along with the letter from Chrysler Historical listing all codes and meanings.

M2 is the only one left out.

Having looked at multiple IBM cards, fender tags, buildsheets, VINs (for multiple cars of FABO members and others) I have never come across anything that definitely answers what M2 is exactly.

I even recall a few conversations I had with Chrysler Historical, I forget her name at the moment, but she sent me copies of other info she had and nothing on M2.

I'll have to look and see if M2 shows up on cars not built at Hamtramck.