OK, I had to go look that up. I've seen those used on truly ancient MOPAR products, like my dad's '51 Dodge truck- "ancient" meaning that that truck was one year older than I. Dodge Bros did things a bit differently, like left hand threads on the left side of the vehicle. They may have worked better, I have no idea.
I note that cotter pins are far more common now, and MOPAR has gone to all right hand threads(?).