Well, we have a nice page on this: Interior/
Interior Trim. And if you look at the illustrations you'll see that the part in question is 03598. Unfortunately the yoyo that created the page hasn't seen fit to include all of the part numbers.
So, here they are, and there is a different one for with and without headliner. Having said that, Big Blue came with a headliner but I've pulled it out and I'm still using the same trim.
Gary, AKA "Gary fellow":
Profile
Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI