There is a cargo carring capacity sticker behind a cabinet in the unit that a sales person could find. CCC is how much stuff you can put in the motorhome with it ready to go with full fuel, people, and full water. It will not include the weight of any options added after it left the factory. The weight of the people is 155 pounds times the number of sleeping positions.
I would still weigh the unit before buying to make sure I can actually put the CCC in it. Some units are at their max rear axle weight so the CCC has to go on the front axle which is impossible. Good luck and you were asking the right questions.