Shocks are attached at the axel and the frame of the vehicle. Yes the shocks are designed to control the unsprung weight of tires and axels going up and down. Also shocks are controlling the vehicle going up and down also even if the axel and tires are not moving much.
So in design match for vehicle the shock has the biggest chore controlling, damping the unsprung forces and not mentioning much some of the bounce rebound of the body. Yes the springs support the load of the body but shocks also dampen the force of the body helping the springs.
It is not mentioned much of the shock design to control the body just more focus controlling rebound of the unsprung weight of the vehicle. A shock deign has both features in the design for the vehicle. You may never see anywhere buying shocks the information you ask.
People that modify by adding much larger tires, or just more unsprung weight will need a different shock than stock to handle this. So the new beefier shocks can also handle sprung weight.
We add weight like a camper even though we are still under the load rating, the rear sags a bit. Do a suspension mode to carry the weight better, Ok the shock are still designed for the truck as the shocks are still working well for the tires and axles as they did not change much toward the unsprung weight of the vehicle.
Add air bags. If plumbed separately they really do add to the effort of the shocks to dampen. You think about it the airbags are mounted the same way as a shock absorber.
Ok I'm just been rambling not typing to precise in the verbiage.
Ski... if you just added support mod to hold up the camper weight and did not go extreme bigger tires etc.. then the stock shocks are fine. But I have always went with replacement Bilstein shocks (the ones sold for my vehicle) for a better performance and heat valving for those darn washboard roads. Those roads sure do work a shock hard and the heat kills off the manufactures stock shocks.
I'm sure there are more questions and only more confusion. I may have just added to it Cheers, Patrick
Note to self... should I proof read this???