My windshield wiper arms are wrapped in some kind of black plastic (99 Eldorado with 66k miles). Unfortunately, that has peeled away, revealing wiper arms (I mean those that carry the wiper blades) that are completely rusted.

Is it normal to have the plastic wrapping around the wiper arms or did the previous owner put that on to conceal the rusted wiper arms?

I bought a standard wiper arm replacement, which is painted black so it the metal parts won't rust so fast.

Is there anything I need to be careful of for installing it, like where is the rain sensor? I definitely don't want to damage that. Also, do I need to have it rewrapped or can I skip that?

Well, the guy at the car shop didn't know how to remove the existing windshield wipers and was afraid he would break that little plastic thing that keeps the wiper in place.

Has anybody experienced problems with changing the wipers?