For a car that looks complete and not too rotten that's a good deal. If it was local to me, I'd already have it washed in my driveway...Ok, maybe not, it's -16 on my driveway and the hose is frozen.
Beginning in '55 , Supers had four holes 49-54 Supers had three holes. 49-54 only Roadmaster had four holes. All others had three 55 -57 only Special had thee holes . All others had four Except 53 and 54 Skylark had none