Chrysler was the last holdout for left-handed threads and finally got rid of them in the mid-60's. Right side lugs were right-handed and left side were left-handed. The wheel studs were stamped with R & L, but not the lug nuts. They were a source of great irritation to young mechanics (and their bosses) who couldn't get them loosened, or cross-threaded a right handed lug nut on a left handed stud. Righty tighty....lefty loosey didn't apply to them.Modern cars now have 4 or 5 lug nuts and with the implementation of very fine threads, you don't need left handed threading.