I got a pair of NOS lower ball joints from ebay and am curious as to how they get pressed in. There is a rim on the rubber top and a lip on the bottom as well. I'm curious if I'm supposed to take the rubber off and if so, there's a lot of (very old) grease in there. I have attached pics.

 

Take the boot off, slip the ball joint into the hole, use a pipe or socket that's the same diameter as the bottom of the ball joint flange and lay the control arm straddling an open vise. Hammer the ball joint into place and reinstall the boot.

 

A ball joint press can be "borrowed " from O ' Reilly's . Like this ;
https://www.oreillyauto.com/detail/b.../67045/4700260
Much easier than the "hammer mechanic " method .