What they say is what you get... With a "Pre-wired" SOLAR setup, you get a connector on the roof (for permanent mounting) and a connector on the side for portable SOLAR kits. Sometimes you only get a side mount. They may throw in a breaker for the roof connector. Someone mentioned that the roof connector has a 20Amp breaker, which limits the Amps you can use the prewire for.
So in most cases for the roof mounted solar you will need a SOLAR Charge controller that you would mount next to the batteries. You can also buy panels to mount in kits that ship with a SOLAR charge controller, one example (GREAT pricing, and many of the members use) is Renogy. You can search Amazon and find them there.... look for the best price of course.
For the side mounted connectors for the portable SOLAR kits, the kits USUALLY come with a SOLAR charge controller.
Most of the members, I believe, would recommend going with the permanent roof mounting over the portable setups.
Check out our RVing with SOLAR social group link below. There is a lot of SOLAR, BATTERY and install information posted there.
Don
My Registry
RVing with SOLAR