...you shouldn't have any problems. RXCM5E4 is the calibration code for the computer. You can certainly update, and there are some new updates available. I have one going up tonight that'll fix the MAF reading on the display (assuming you even use that one) among other fixes. Honestly though, if the truck runs fine and you don't experience the "shudder" on level 3 that everyone was complaining about, I'd leave it alone.

If you have any other questions, let me know.