The attached photo was found in the "Radar Trailers" thread, it shows a cab 13 with what appears to be a 2B1 body in what appears to be a factory setting, possibly during manufacture. This makes me think that a 2C1 might be inappropriate on a cab 12. Again, others may be able to prove it one way or the other.
I am sure I have seen a production breakdown by year and capacity of truck. I think that I have seen something on how many cab 11, cab 12 and cab 13 were produced, but have no idea where I found it.
It would seem to make sense that proportionately fewer cab 11 and cab 12 remain since they were exposed to the hazards of war for longer.
I hope the new owner will show us photos evey so often.
Linked from "Interesting pic of CMP"