There is a Stock Tune and a "Stock Tune". The Former one is from RAM and later one is from a tuner who would modify a few things but would leave the power settings unchanged.
If you want to go to Stock, only dealer could do that.
I wonder though why you want to go back to stock? You know that your (deleted) truck won't run on a stock tune, right?
Before you attempt any of these you will need to get a tuner (ZX Lynk, EFI Live, etc) and have a delete tune ready to load into your truck once it rolls out of dealers bay door.