If it’s a real brick-and-mortar dealership, with a showroom, a lot full of cars and all of that, then it should be easy enough to look up in the Yellow Pages (either paper or “virtual” online) and view it in a viewer such as Google Earth. That is, you could verify that there IS a dealership at such-and-such an address and that they have a name and phone number.
That’d give you at least a start toward knowing that “it’s a real dealership”.
However, I believe that there are also “virtual dealerships” of networked buyers and sellers who simply contract for all of the services required to detail a car for sale, to provide required maintenance, show cars to prospective buyers, etc. My boss, who is a real “car guy”, routinely contracts with people out of state whom he deals with online only, and frequently drives (from Connecticut) as far as Michigan, Pennsylvania and New Jersey to pick up cars that he has bought – sight unseen (other than photos and descriptions) – and then drives home again, and later sells himself more or less the same way.
I can tell you that my boss is “totally legitimate” in all of his dealings; if he said that a vehicle was in “such-and-such” condition, then (knowing him) I could take that to the bank. (I also know that some sellers have attempted to rip him off by selling him misrepresented vehicles, too, and he doesn’t take that lying down!)
So, that’s possible, but I wouldn’t try it myself knowing only what I know about cars.
As for “the social impact of taking money out of the local economy”, I’m trying to stifle my laughter at the silliness of worrying about that for even two seconds. One second, okay.