This probably varies by state, but here in Iowa, all of a dealers inventory, new and used, is classified in a category called, "Dealers Registry" until such time as the auto is sold. When I'm given a service loaner, they must put license plates on the car that say "Dealer", then a license plate number. Using these "Dealer" plates must also be used when driving a pre-owned car or a new car.
When the car is sold, it then becomes registered to the new owner. Given this process, the car is never truly registered to anyone until it has a true owner and, the registration and license fees are paid, and the state gets it's taxes.
As for Car Fax, If your car has never been sold before or registered to an individual, what would you expect to find?
Paul, where do you live in Iowa? We lived in Cedar Rapids and Davenport (Quad Cities) before moving to the Chicago area.