Many, many trucks are "overloaded" according to the gross weight limits.
A few hundred pounds is not too much to worry about, but be careful how much stuff you pack as that weight adds up quick, to hundreds of lbs.
What is the limiter for the truck? The truck frame? No. The tires, the wheels, the axles, the springs???? Some of these can easily be over-come like wheels and tires. Rear springs can be helped with air bags, or helper springs or other devices (front springs are usually not the issue).
Consider that a 1 ton and a 3/4 ton truck usually are identical except for the springs, then many times it is the springs that are lacking.
If your truck can handle a 2,000 lb payload and you are looking at a TC that, loaded, will be 2,500lbs, then you can fix the truck. However, I would not get a 5,000lb TC and expect much safety out of the truck unless you do heavy modifications.
Actually, if your truck says it is good for 2,000lbs payload then you will have lots of company with others who over-load their truck by 500 lbs with thousands of miles of no issues.