"NEW" simply means it has not yet been titled to someone else. Dealers use vehicles on their lots all the time for sales/service managers to drive, and they can rack up a few hundred miles if not more w/out the truck being considered "used". When I bought my '08 FX4, the sales manager had been using it for about 600 miles worth of driving, but the truck was still pristine. I was able to use that to bargain down the price just a tad, but not much.
Long story short, I don't find what you explained to be "antics" by your dealer. He's likely got '13 models that have been used by his staff but are still "new" and he's looking to unload them now. I would just try to make a great deal with him on them considering their age and mileage, and knowing he needs to get them off the lot before the '15's come out.
2014 FX4 SCrew : Tuxedo Black : 5.0L V8 : 3.73 E-Locker : 402A Pkg : MFT : 20% Tint : Custom FX4 Decals : 20" FX Wheels : AS 1.5" Level w/ 2" Rear Blocks : Cooper STT Pro 295/60r20's : F150lifts.com GLK
Build Order Date: November 26, 2013 || Production Date: December 6, 2013