15 inch rims

I have a set of 4 but only 1 has ID numbers and letters. See picture.
Can someone identify this rim ?

Thanks, Paul

 

Those are 71-72 Built August 20 71 if I am reading that M code right so they would have come on a 72.

 

If the other 3 have no I'd. Are those made after production?

 

Tough to say. I would examine them closely to see if all the contours are the same to see if they are actually the same. Look at the backs of the center part of the wheels. There are usually more date stampings. See if those all match.

 

ok thanks