decode vin.....

M2 is definitely Plant. I got my IBM punch card, aka build card, from Chrysler. Column 22 is labeled PLANT and has a punch at row 2: so 222. My car has very few options, 4 to be exact, all accounted for on the fender tag, with M2 being the only one left and 222 being the only 'punch' left on the build card.
Other members had also informed me that it was the plant code before I received my build card.
I've noticed that fender tags with a date of September through December; 9, A, B, or C, do not have the M2, which would be a build date in 1966, but fender tags with 1967 dates, January through June; 1-6, have the M2.
I've never seen a 68 tag with the M2, but if one does it could mean something different.