On most evaluation forms, there is a place for grades. So, the call back interviewers may check grades good, or fair, but not exceptional. That will be one item in the equation, but we really look at the overall comments from the interviews.
If you are asked about the grades, you need to explain in your best way without getting flustered. If you did have a medical issue or family death, it is ok to generally reference it. If it was a first semester thing and you were getting used to testing style, etc., it is ok to say that. End on a positive note...although my grade in civil procedure first semester did not meet my expectations, I turned it around second semester... something like that. We like to see progress especially from first semester forward.