Wow. That story just got better and better as I kept reading.
I wonder what kind of "FAA records" exist that show how many hours a non-certificated pilot has flown in a non-registered airplane.
While not proof, if the previous owner still had logbooks with tach/hobbs time near the time of the theft, and it was recovered with 1200 more hours on it, they are probably making the assumption that he flew all those additional hours on the plane - which may or may not be the case.