2010 KOP CIM motors vs. 2011 KOP CIM motors

[RJHermens]

Our team was thinking of using two CIM motors per CIMple gear box (total of four) but only two of these motors came in the KOP. However, we do have several of the KOP motors left from last year. The old and new motors look virtually identical but have different serial numbers. Does anyone have a spec sheet or know the difference between the two? Or is there a difference? And would it cause a problem if we mixed and matched?

Thanks!
-Ryan