Elvis license plates

Can someone explain the 1 ELVIS licencse plates? Last night l was watching an elisode where a legitimate Elvis owned Cadillac was sold. There were license plates on the car that said 1 Elvis then today another episode with a pink Cadillac that had the exact same license plates, 1 ELVIS on it. Is there a license plate set for that state that says that? Or are they planting the license plates on the show?