I'd guess that they are both K Frame panels. The right grip cannot be a N- Frame SN, because at 305XXX I believe that the diamond centers would have been eliminated... Also looking at them from the top side they appear to be the same size. Because of the angle of the photo, I think the back side photo distorts the right panel so that it looks a little larger than the left. But easy enough to see if they are put back to back...
