r/r window regulator motor.

Hi Everyone,   I'm new here and need help on replacing the window reg. motor on my 91 Seville.  I have the manual and it tells me to drill a hole in the sector gear and through the back plate, put in a nut and bolt to keep it from letting loose at the wrong time.  There is a hole in the interior door panel, is that where I drill?  Also, I don't feel a back plate behind the sector gear.  Any advice will be appreciated.   

Hi again,   Finally did some testing on my window motor/regulator and found the the trouble is the express lower module.  G.M. has what they call a "glass and hardware control module" for 95 bucks.  Can't find a picture of it so don't know if is the right part.  Any ideas?     Jim