Many paint shops would rather use masking tape than take the extra time to remove the chrome trim. But in doing so a lot is sacrificed in the quality of the job. Why not take it off yourself; it is easy and it will not be all buggered up when you get it off.
For those of you installing a new rear window, particularly if you are installing a glass rear window, you may have wondered ? do I put the rubber molding on the glass and then fit to the top or put the molding on the top and fit in the glass?