it also depends on what time of year, and what time you're trying to get a seat. If you're going to be there during a very busy time of year, probably not a chance. But if it's a slow, to moderately busy time of year, you might have a chance if you're willing to eat early. If you really want to eat there your best bet is to get an ADR.
Last May, mid-week just before Memorial Day Weekend, we had ADRs at Le Cellier for 5:15. When we checked in just after 5:00, they were taking walk-ups, and telling them 15 minutes wait time.
In January, just after MLK Jr. Day, when we walked past Le Cellier, we heard a woman telling her family the good news they would be seated within 20 minute. Again, that was for a fairly early dinner seating.
I would guess it's like all the other restaurants with getting backed up more as you get later seatings.