Yes. The heim joints shouldn't be able to move into the range of motion where they will bind, and will ideally start out in the center of their range.

Cheaper ones will move around in the race, yes. When good ones do that, it's time to replace them. If they're that worn, it's possible for the spherical to pop out of the race and that isn't a good thing. I would really, really doubt you're actually hearing that though because that shouldn't make much noise unless it's really, really sloppy and under load... So it's possible that they're getting articulated out of their range of motion, but other than that I'm not convinced that's where the noise is coming from.