Though they are not required, should you have a large group of people that might be a good idea.
Yes, you can make reservations, but they're not usually required except maybe holidays and such.
I'm not sure if they reserve in advance. I've never had any trouble getting a table when i walked it. I would suggest an old fashioned phone call. One of their staff would be best qualified to field questions about reservations from day to day.
Thanks! Your answer is awaiting moderation.