I would have to agree... Ford has overbuilt the trucks, half, 3/4 and 1 ton trucks for the past few decades. Not sure one the newest ones, but on the 70's - 97 and I figure the newer SuperDuty trucks are probably this way also. Ford has always seemed to realize that people are going to use their truck, as a truck, and have underrated them for safety reasons. I've not loaded up a newer truck, other than an 92 Ranger, and had it pretty heavy, but we had a 73 F-250 Regular Cab 2wd, 390, C-6) that I know for a fact we had 475 gallons of water in one of the green pickup water tanks. Mom and Dad live in the country and have a shallow well, and for several summers during a slight drought, the well would go dry, and we had to haul water. We filled that tank completely one day, not to the 450 "full" mark, but to the lid. So 475 x 8 lbs per Gallon = 3800 gallons of water, plus the tank and a platform we built to angle the tank to help empty it, so at least 4000lbs in the bed. Truck would go fine, stopping was more of the issue, it stopped, but just not quickly, just like pulling a heavy trailer. We have also had cut firewood, stacked in the bed, high as the cab, front to back of the 8 foot bed. That was a heavy load also, no idea how heavy, just hauled it home. A regular load in the truck was out IH Cub Cadet 149 with a tiller or a mower, most every weekend, all spring and summer. Hardly knew that 1200lbs was back there......
I would think 2000lbs in the bed, properly secured, should be ok. Your truck, so your decision.......