I believe this means that the part's computer has the vehicle's VIN loaded into it with a computer that can only be purchased/used by a certified technician. If he was to buy a new part, it would have a blank VIN; and if he pulled one from a junker, it would have that car's VIN.
(edit: should also say, I think a VIN mismatch would cause the ECU to refuse to work with that part and shut down)