It depends on when you are going. If you are there during the busy period, then you may not be able to et anything the same day. If you are there during the less busy period, then you may be in luck. Don't let that stop you from calling that day to see if anything is available, no matter when you go, because you might be surprised.
We were a party of four and got a reservation the day of. It was January and we were at the late meal and we sat at the table right behind the light guy, but we still loved it!