windshield please help

Had a new windshield installed, in 74 duster with new seal. Windshield leaks around bottom about 6" from each corner, my question is does the o-ring go in the groove all the way around the windshield. The installer said that it didn't and cut it off about 6'' from each corner at bottom and that's where water comes in. Took the car back and they say it is a body seam leak,I say he's just didn't want took lick his calf over.
THANKS IN ADVANCE PUP JOINT