In a sense yes the antifreeze that you buy and put in your car is also coolant for your car as well.
Although Antifreeze is basically just coolant with Alcohol mixed in with it to avoid the coolant from freezing up and damaging your engine.
Antifreeze must have the proper mixture of water and coolant as well as the alcohol to prevent freezing.
However the Antifreeze that you put in your RVs plumbing system will not work as coolant so Antifreeze itself is not coolant but the Antifreeze you put in your car is the same thing as coolant as it prevents freezing of your engines system and cools the engine down.