The Health of Target of Target (if that is what you are referring to) is available to anyone with or without Leadership points, but you only get it to show and work if you are in a group or raid whose leader has that ability.
So the answer is no, it is not restricted to only those with LXP, but IS restricted to only those in the group or raid of someone who has purchased that ability with LXP points.
If this was not what you are asking, my apologies, and ignore my comment here
