Crane closed in January.
The original 273 & slant 6 rockers are a friction lock design.
The ones sold by the performance aftermarket are designed to use a lock nut.
The one on the right looks like a Crane 99780.
I don’t know what you ordered, but that’s what it is.
3/8” threads & 3/8” ball.
The 99802 is 3/8” thread & 5/16” ball.
That’s what would have come in the typical Crane iron or gold rocker for a Mopar.