There was no bullet hole in the windshield, but there was a dent on the INSIDE of the metal trim around the windshield, indicating that fragments from BEHIND hit it. There were cracks too, on the inside of the glass.
Please see http://www.freerepublic.com/focus/f-backroom/3599765/posts ... and remember the testimony from Ford Motor workers that replaced the windshield 2 days after the assasination.