Did Ford produce 1968 Mustangs with Q-code 428 Police Interceptor engines?

Kevin Marti confirms that the records his company has licensed from Ford do not include any 1968 Mustangs equipped with a "Q" engine code. The VINs I've seen for alleged Q-code cars have all turned out to be cars that originally left the factory as C-code (289-2v) cars, meaning someone modified the cars and altered the VIN - and that's not legal.