I can't say for sure if it is pre-wired but I would suspect it is. It is cheaper from a manufacturing perspective to run the wires so they are there when the option is selected. If you knew what color the wires are you may be able to find the in the slide wire loom.
Keith and Lisa Ward
2019 Pinnacle 36FBTS
2021 Ford F350 XLT CC LB DRW 6.7L Diesel
Demco 18K Autoslide Hitch
2019 Ford F350 SB 6.7L Diesel (Gone)