I'm assuming this is for the AMCAS? I think that you put in the date that you took the class and classify it under your freshman, sophomore, junior, or senior years/semesters. So depending on when you matriculated, I think that the class could be either. I had one class that I took during the summer of 1997 which showed up as if I took it the summer following sophomore year. I was questioned about it a few times, but I explained the discrepancy and it was fine.
I would just go ahead and classify the course according to your class year at the time you took it (i.e., what were you in 1996 or 1997, FR, SO, JR, SR?).
Hope this makes some sense.