They look legit. They've sold other cars, including a Roadster in the past. Same contact info as this listing, which mentions locations in both states: 2010 Used Tesla Roadster Roadster at Gambacorta Motors, Inc. Serving New Castle, DE, IID 8835868 Which was also discussed in this thread: #770 - Racing Green - Boulder, CO
How did they get this car? Is it a Get Amped! Tour vehicle? I'm very surprised that they got ahold of a Signature S so quickly.
Looks like someone accepted delivery and immediately turned around to sell it without ever driving it.
Maybe it's Kimbal Musk's car? Isn't he in Boulder? And I think he had a black car... I could be way off here though... Technically that would be a Founder's car though...