You would need at least a wiring adapter harness and either some form of resistors/error cancellers or get AlfaOBD and change the BCM settings for the tails to LED.
This.
The pigtail on the LED taillight is different than the connectors for a non-LED taillight. IIRC Big Horns couldnt get LED tails, so you will need to adapt to the LED pigtail.
All of the halogen to LED adapters Ive seen have resistors/CAN bus adapters already wired in. If you have AlfaOBD you wont need them, but unless you make your own adapters you'll still end up with them anyway (and Im not sure how them being there would affect things if Alfa is used to tell the BCM there are LED taillights)
I actually made my own adapters because my tails didnt have the factory pigtail (which is almost impossible to find, BTW), so I go right from the stock halogen connectors on the truck directly to the LED taillight sections, all using the correct connectors so no cutting was involved.
