This one is a bit confusing. Dealer Description shows 8200lb payload package.....
\http://www.kunescountry.com/New-2013-Ford-F-150/vd/17611357
But window sticker shows 7200lb package.
http://services.forddirect.fordvehicles.com/inventory/WindowSticker.pdf?vin=1FTFW1ET6DKG20282
Here is another 7200 GVWR.
This one lists the 8200 GVWR and the 3.5 in XLT trim. VIN 1FTFW1ET9DFD79441 . But the window sticker shows 7350GVWR.
http://www.herringtonyoakford.com/2013_Ford_Ford_St.%20Marys_WV_212287441.veh#
http://www.inventory.ford.com/services/inventory/WindowSticker.pdf?vin=1FTFW1ET9DFD79441
I can see why your search has been difficult.
Good luck.