John Pace's drawing shows what used to be there.
If you can find a suitable spring and ball, fit them, and just stake the edge of the insert to retain the ball into place.
The spring loaded pin arrangement gives better retention, but the sockets have to have a through hole for it to fit into.
Removing the socket is less easy, since you need a small rod to press in the rod, to release the socket.
Can be a right PITA, definitely slows working.
IMHO stick with the ball and spring!
Howard