Garage Cabinets, Garage Storage, and Garage Organization

Just picked up my 1991 BMW 520i (E34) yesterday, on the way home, I tried to lower the drivers window. Nothing happened although I can hear the motor working. I lowered the motor arm and pushed the window which promptly fell into the door. Fortunately, I caught it and wound the window motor back up which holds the window safely in place. My question is this, I know that BMW are well engineered cars and would like to know if there is any problems I will encounter when removing the door card. My intention is to replace the brackets on the base of the glass as they appear to not be holding the glass at all. Thanks in advance for any advice.