My 2007 Jeep Liberty has experienced regulator failures on all four of its windows. I purchased new regulators and have been successful on replacing the front door windows. However, on the rear passenger windows, I have run into a problem with the glass - each window has a black strip at its base which appears glued on and prevents the new regulator from "clipping" into place. Are these black strips removable (without breaking the glass) or will I need to purchase new rear windows to match the new regulators? I appreciate your time and advice. Thanks.