The pic that shows the driver's side makes it look like there's a lot more room between the front tank filler and the front of the box than there is between the filler and the wheel opening. On my '97 short box the distance between the filler and front is about twice the distance from the filler to the fender. So if the filler is in about the same place in that year as it was in '97 I'm thinking long box.
And definitely a round fender, not an '80 - '86, if that's important to you.
Bob
Sorry, no '80 - '86 Ford trucks
"Oswald": 1997 F-250HD crew cab short box, 460, E4OD, 4.10 gears
"Pluto": 1971 Bronco, 302, NV3550 5 speed, Atlas 4.3:1 transfer case, 33" tires
"the motorhome": 2015 E-450-based 28' class C motorhome, 6.8L V-10
"the Dodge": 2007 Dodge 2500, 6.7L Cummins