300CE window regulator
 

My driver's side window won't roll up to the top anymore.I removed the door panel and could see the last 3 teeth are broken off.(it was making a noise before).I checked on fastlane's catalog and the regulator is available w/o the lift motor.
My question is do I need to remove the 3 rivets or does it just unbolt?The CD is a little confusing as it has two different procedures-#180 removal and installation of window lift (power window) on drivers door-describes unbolting.
#185 removal and installation of electric window lift on drivers door-describes drilling out rivets and unbolting.
Is it the lift motor that is riveted in place?
Could new teeth be welded and ground to shape?
Any help would be appreciated:)