I believe with the 3:73 axle and gasser, the heaviest trailer you can pull (per the truck ratings) is 9900 lbs. With the 4:10 axle and gas 6.0, the rating jumps to 13900.
The pin weight of 1955 is dry pin weight. Ignore that. True pin weight will be calculated at around 20 percent of the loaded fiver weight. A fiver with gvwr of 13,900 will have a loaded pin weight of around 3000, which is too much for your 2500 or any 2500 for that matter.
With your truck, I would recommend a fiver with a gvwr of 10,000 or less. The truck in my signature with 4:10 axle (gasser) has a gvwr of 10800 (scaled payload of 3900). My fiver scaled weighs 12,280 loaded with a pin weight of 2500. This scenario is a good match for my truck. I am only offering this information for comparison sake.
Steve