yes they are still $2.50 - i had one three weeks ago and it was delicious!
as for my time dining, you dont have to book but where you have a big group of people i'd say it was a must. in our case, it was 15 - so we called from our room at some point in the day and all went at the time we'd gone for.
stick to the main dining room on the formal nights - the standard of food goes up a notch. fillet of beef one day, lobster on the other. cant complain!