The only real way to tell is to take a look at the drive train. right away when you look you will notice the front of the cans are completely different. 2012 less metal, 2013 more metal and 3 pieces.
Originally Posted by Reaper (ACI)
Externally you couldn't guarantee which it is.
Pull the drive train out, then it's obvious.
2012 (1) piece can
2013 (3) piece can