TransEngineer, is it possible to upload or "reflash" the 2012 codes/shift patterns to the 2013?
Unfortunately, no. The engine and trans software is combined in one controller (the PCM), so the only way one model year's software carries over into the next is if there are NO changes at all in the engine OR trans software (which basically never happens). The dealer scan tools (that do the reflashes) are programmed to only allow a certain (EPA-approved) update path. That is, they check the current software version that is in the truck, and then only allow a reflash with any "approved" update for that specific software version. For example, if you have software 4567AB it might let you reflash with 4567AC, but not with 2832AB (the software for the previous model year).
So we have to wait, and hope they approve a service flash for 2013.