Not a Vanity Plate, but our campus doctor at the first college I went to outside of Boston, in Milton, MA

had a 68 Cougar with the Plate number of '1'....

He use to joke he could park anywhere in Boston and never get a parking ticket...

cops must have figured the car must belong to someone really really important...

His family had been issued the first license plate in Massachusetts way back when... and it had remained in the family ever since...