drilled out then put a flat head screw driver to turn the locking bar clockwise?

The backglass needs to slide up and once the backglass is lifted out of the bottom channel lean the bottom forward and remove the backglass . A screwdriver in the drilled out lock should work to turn the lock bar . The lock bar prevents the backglass from sliding up enough to remove it that is why it needs to be turned out of the way .