They see as much as you submit for them to see. There is a period during November where you can update your grades, but if you've interviewed before then this may be insignificant. However, this is the only time that it can be updated once. Some schools may ask for them if you interview in January if they are looking for improvement or how you did in a pre-req course.
Some people have also been accepted depending on their final transcript (most likely due to pre req courses)