Maybe try the 07-14’ part? That’s a total crapshoot though....in this 2008 brochure on page 4 it clearly states the off road package includes fuel tank, transfer case, and engine skid plates. Maybe a search for off road package equipped trucks will yield a result. No clue.
http://www.auto-brochures.com/makes/Ford/Expedition/Ford_US Expedition_2008.pdf
http://www.auto-brochures.com/makes/Ford/Expedition/Ford_US Expedition_2008.pdf