fender tag 67 cuda

I am unable to decode one item: M2.

Any ideas?

Also, I have a 12 stamped across the UBS perpendicular to it.
So its:
UBS with a B under the U.
1 under both the B and S.
2 above the B amd the S.

The 12 is in a different font and sideways.
It is not very clear in the pic, but it is clear when looking at it.
I removed the fender tag, and it appears it has never been off the car.

Any ideas how this happened or what it means?

Attached Images
Author: admin