Not required, but recommended!
If you get there right when it opens, then no. If you wait any longer you will not be able to
We were able to get a table at dinner time (5pm or so) on a Tuesday when the shutdown was going on without a reservation. It got really busy right after that.
Yes and no. If you get in line right as they're opening, you should be able to snag a seat at the shared table.
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