10 bolt rear end identification

[brianp01]

Hey guys here are few pics of the rear end on my '59 pickup. It is a 3200, but I'm not sure if it is the original rear end. I tried cleaning up the passenger side axle to find any stampings and all I found was the code: MA1 26, stamped on the left, front side of the housing, can't find anything on the axle tubes.

It's a 10 bolt, at the widest width it is 10 5/8", the pinion nut is 1 1/4". It doesn't seem to have the ears at the 4 and 8 o'clock bolts, but there are slight nubs there, not sure if that helps.

I've searched a lot of blogs and websites to find this code but haven't come up with anything yet. Anyone have any idea what rear end this is? Or what that code means?
Thanks,
Brian