I did 3 of them. The new (brand new) 4wd had the coax in the back right corner post, but no power cable. I did not tear the FM radio pod down to check, because the book and internet said it was in the post. I just buried the power cable in the rubber trim down to the factory power pod and hooked up with female spades.
The 4wd and Sprayer cabs are a few years old, and both of them had the coax and a switched power lead laying in the FM radio pod. Made it real easy. And they leave the plate to right of the FM above the headliner all clear, so you can put self tappers right in for the bracket.
Worked out well. I did have to end up putting a different antenna mount on the older 4wd, something was wrong with the factory one, and it was much easier to replace than try to get to it. I used a Stainless mirror mount NMO on the grab rail in back of the cab. Works great.