The answer is...it depends. Do you order an appetizer, entree, and dessert? When are you going? Are you fast or slow eaters?
Generally, the rule of thumb is allot about 90 minutes for a TS meal. So based on this, you'll be cutting it a little close, but I think LTT is one of the faster meals. My lunch last year took a little more than an hour. So, you'll probably be okay, but personally, I dislike spending a meal looking at my watch. I'd rather enjoy my meal and not worry about the time, so I'd try to get an ADR for closer to 1 pm.
You can probably speed things up a little by order everything at once, asking for the check as soon as possible, etc. Luckily, LTT is on the parade route, so hopefully there will be spot available near the restaurant.