Either. My spl rear arms and traction arms do both. I believe the camber joint was very solid while the traction was loose. If you install, use a pry bar to see if the joint separates or has play. That's a bad one if it does.

Thanks!

I pushed and pulled on both ball joints and they seem firmly seated in the socket with no play.

I just received confirmation from SPC and it pretty much lines up with what synolimit said.

"It could be that one of the ball joints has been recently replaced by the previous owner. Usually a used ball joint will exhibit the smooth behavior that you described, while a new ball joint will still be very stiff. As long as you can't push the ball joint stud in and out at all, you should be good using those ball joints on your arms. "