FYI:
Not all year, make, model, Mopar automobiles use the cottor pin arangement on lower control arm shafts, pins, (whatever you personally refer them as)
All A body cars from the beginning, use a self locking nut on the threads of the shaft.
The cars that used the cottor pin on the shaft were early 60's B Body cars till sometime till the mid 60's.
After that they used the regular self locking nut. Same with the E body cars.
Cotter pin shafts, that use a castle nut, or others that use a self locking nut have got nothing to do with the op's situation.
But you don't interchange nuts from one style shaft to the other.
