As was stated above, CDL isn't determined by actual weight of truck, but of GVWR (gross vehicle weight rating). You could have a vehicle rated for 30,000 lbs with a curb weight of 12,000 hauling packaging peanuts that might be a total weight of 15,000lbs. CDL needed because truck is rated for over 26,000.
You could have a vehicle rated for 25,000 overloaded at 27,000, and technically, no CDL required...but there are other laws at play, and your insurance may refuse a claim if you cause and accident.
With a trailer if: if the combination of the truck and trailer goes over 26,000 AND the trailer is rated for more than 10,000 you need CDL. If you have a 25,000 GVWR truck and a 9900 lb rated trailer, you are good to go without. But a 14,500 rated truck and a 12,000 trailer needs CDL.
So to answer the "real" question (not curb weight...that means empty weight of truck...as it sits on the curb), the first Google hit says:
"The F-650/F-750 GVWR range starts at 20,500 pounds with the F-650 Pro Loader, and can go up to 29,000 pounds for the F-650 straight frame"
It would be good to know your curb weight too. That way you know how many chips you can blow in before you exceed the trucks GVWR. That's gotta come from a scale. There are too many different configurations. If a major supplier put the body on the truck, they may be able to tell you pretty close...