I must have gone completely crazy, eh?

I'm swapping my spring back to stock today and found one of my lower ball joints with a split boot. I don't have a new spare on hand and need the car going by tomorrow AM. Considered robbing one off of my spare suspension, but it'd destroy it in the process.

Dug through my front suspension parts box and came up with a special set of lower ball joints. These were given to me by the original owner of my 67 Wagon. and they are not sealed. These have Zerk fittings on the bottom, and the rubber cap is just an open rubber cap that protects the top of the joint. The grease keeps the cap sealed against the "dome" of the ball joint.

I cleaned one up and checked for binding and movement, and then re-greased it. Seems good, so I went ahead and installed it.

I may do the other side later, but that one has a cracked rubber cap on top.

My questions are about this design. Is anyone familiar with it? How often should I grease the joint? Can replacement rubber caps be found for this style?

And of course - am I completely nuts for using this type of ball joint on my car?