While the phrase "wired for solar" may just be a sales gimmick, the wires may be installed, but are they of the correct type and location? Who knows?
I find the actual implementation of a solar system has several steps, requiring different equipment and wiring. Most are custom installs to complex power management systems. I find it takes a LOT of research and study to learn about solar systems, charge controllers, PV cells, and battery maintenance. As well as one's expectation of what will the solar system be providing energy. With solar, much like a generator, one needs in-depth knowledge about the energy demands of the equipment, TVs, lights, microwave, pumps, AC, etc.
And to that end, many of the lesser expensive solar systems have been found to be electrical noise generators, interfering with TV and radio reception.