I requested an odd row when I made my reservation, and they said they would note the request and try to honor it. We did end up with an odd row, and the view was great. The CM didn't act at all like it was out if the ordinary to make the request, so I would definitely recommend asking. It can't hurt!
Also, I believe the seats are pre-assigned, as the paper we got at check-in already had our seat assignments on it.