When Susan enters the bar, she tells Sam that her lawyer told her she needs the VIN number of the Corvette. The VIN number would be on the title, which she should have if her husband actually bought the car.
Sam rattles off the VIN number of the Corvette from memory, but it's invalid. Corvette VIN numbers started with numbers, not letters. A fake VIN was used for obvious reasons.
Near the end where Sam is in the dog house in the kindergarten class, between scenes, we see the exterior of the school he's in. On the flagpole is the American flag and the flag of California, not Massachusetts.