Yup. Definately call ASAP regardless of month. I started booking for October trip back in June (a little late), and LeCellier is all booked up for the desired times. Most other places I was able to book.
Also, Dining told me that multiple reservations on the same day would result in earliest called in reservation cancelled! (I used to do multi-reservations for dinners at diff parks in case we changed plans on where we were going that night!)