How do I know which one is the left one and which one is the right one?

They can both be installed on either side but Im guessing they are not the same.

Im getting a squeaking noise from the aluminum collars I used to replace the rubber bushings on the 22mm itr swaybar because the endlinks are not rotating but rather the collar inside the swaybar is, or maybe the enlinks are squeaking but I doubt it.

thanks