I asked about this specifically when we were there a couple of weeks ago. Although it may appear that way, tables are NOT pre-assigned. The host said that guests "are seated on a first-come, first-served basis." He commented that because we were third in line, we would pretty much have our pick of wherever we wanted to sit. He told us to just let the seating host know when we got down there. It does pay to get there early if you want a specific table type or location. They won't ask you where you want to sit; they will just take you to a table. BUT you can move if a different table is available.
The exception might be if you're a large group and they need to put you somewhere together, or if the remaining tables are for a large group, etc., or you're a group of 2 that has to be seated with another party.
They do go around through the line checking reservations and number in your party, but evidently the purpose of that isn't to pre-assign seats; it's just to be sure they have a spot for everyone.