Exactly,
All D200's have a total front and rear axle rating of 8300 lbs.
All D200's have a total GVW of 7500 lbs., which should never be exceeded.
Your truck has a total front and rear spring capacity of 10,350 lbs.
Your truck, being that it has a "Camper Special" option was built knowing that it's load will have a high center of gravity vs loading it with dirt as an example. Increasing the spring capacity's means it was built for a specific application it doesn't mean it will carry more payload.
Although, in theory you should be able to be loaded at 8300 lbs.(5500 rear/2800 front) safely, but not legally.

Same follows through for all W200's, they have a GVW of 8000 lbs. vs your 7500 lbs. It doesn't mean a W200 can carry more payload, only that the truck itself weighs more, because it's a 4wd, so they had to increase the GVW rating to allow it to be capable of carrying the same amount of payload as a D200.

Mark D.

1968 W200 Sweptline
1969 D100 Utiline
1971 D100 SE Sweptline
1993 D250 Club Cab Sweptline
1986 W250 Cab & Chassis
1978 D300 Sweptline

E. Brookfield, Massachusetts