Well, from Carson City/Reno, Nevada, 76 years old, and have lived in Nevada since 1862. For many years, I traveled all over the state on business, and had friends in two-thirds of the small towns, if not more.
I have to disagree with the non-use in the West comment, albeit in a slightly different context. I often heard, on parting, someone add "Say Hey to {John, Mary, &c.]" Not a greeting to the individual, but a request to pass along a greeting and remembrance to someone "hello from ...."

Mark Twain, in a letter to Bob and Louise Howland, used the phrase "It's a great country--Hey, Bob?" in an 1870 letter the context seeming to mean "Isn't that so, Bob?"