Typically for a test drive on a corvette they should have had some basic information of the person in the first place.
Driver license as well as a copy of there insurance card. And seriously if it was a test drive they should have already discussed some numbers and got some contact information.
I would bet it was more along the lines of the car was left outside and someone inside the dealership got the fob for the car and gave it to a someone who came and stole it.