Left vs right hand thread wheel studs.
LH studs on left of car (drivers side) Rh studs on right side of car (passenger side). General motors had the lefties too until '64 if I recall correctly. So did some of the others like Studebakers until '63 (I think) and various other brands I don't remember because I don't work on those any more. Mopar was the last hold out.
Just this spring a friend took his 62 Bonneville convertible to get new tires and the shop broke off all five left front wheel studs before they came out to the waiting area to tell him his lugs were so rusted they were breaking off. He told them to look at the work ticket which he had the counter person write in big letters, "Caution, left hand wheel lugs on this car." Fortunately they didn't break the rear ones too. He made them source some left hand studs to replace them with. He had to leave his car for a couple of days until they could FedEx some studs from Arizona.