All restaurants allow walk ups, if there is a table available. Question isn’t one of policy, but of how busy they are.
And, how busy they are can vary day by day at some restaurants (BOG and CRT almost never have walk ups available, but they COULD, if someone were to cancel last minute).
Does TE have regular walk up availability? I don’t know. You can check the ADR availability for within the hour a bunch of times and see what you find. That will be your best bet. Best to check at the time of day you were considering going. Check a bunch of days to see.