Definitely make dining reservations for both. You likely don't need to make the reservations today or even this week, but the sooner you do so, the more likely you'll get preferred dining times. Blye Bayou is very difficult to get into at the last minute. BTRBBQ is more likely to book up these days since it will be closing forever as of January 10th.
Also,better to make reservations now and cancel 24+ hours ahead than wait until 24 hours beforehand and find out there aren't any reservations left. It doesn't cost anything to make reservations as long as you cancel at least 24 hours ahead of time.