The difference between 2012 and mid-2013 MY's shifters were noted earlier, here's the instructions for newer 6MT's. See post #396 of this thread for a picture of the newer shift tower.
1. Remove the floor console. Refer to Front Floor Console Replacement.
2. Lift upward and disengage (do not remove) both cable lock adjusters (1) to release the internal cable assembly, one for each side.
3. Block the shift control housing, push the selector lever (2) backwards and push (arrow) the blocking device (1) towards the shift control housing.
Note:
The hole of the transmission gear control (2) must be aligned to the hole in the base so the pin (1) can pass thru both. The transmission gear control will be locked in the 1? neutral position.
4. lock the position of the shift control lever by rotating the reverse lockout device with the following instructions:
Push down on tab (1) and pull up on device (2) to release from installed position.
Rotate device 180 degrees so tab (1) is in the rear of the shift control assembly.
Secure integral pins (4) in holes located on shifter base by pushing down device (2).
5. Secure adjuster locks (3) by pushing down until locked. One for each cable.
Note:
During this procedure DO NOT touch or preload the fixed shift lever as this may cause mis-adjustment to the shift system.
6. Reposition the reverse lockout device with the following instructions:
Push down on tab (1) and pull up on device (2) to release from installed position.
Rotate device (2) 180 degrees so tab (1) is in the front of the shift control assembly.
Push downward on the reverse lockout device (2) until tab (1) snaps into detent
Note:
When unblocking the blocking device (1) a defined snap noise should be audible, a snap effect should be felt.
7. Unblock the shift control housing, push slightly the selector lever (2) backwards and pull (arrow) the blocking device away from the shift control housing.
8. Install the floor console. Refer to Front Floor Console Replacement.
9. Verify correct operation of the transmission control assembly.