It's never too late....but your choices may fill up. You may have less flexibility in available times.
Just a suggestion--before I call, I have my schedule for the week. In another color of ink, I indicate on my notes what I might consider as an alternative restaurant for that night or nights that I might be willing to switch the choices. For instance, it might not matter to me whether I eat at Chef Mickey's on Tuesday and 1900 Park Fare on Thursday or if they are reversed....
I was lucky this trip. We booked about 60 days out, and I got everything I tried to reserve. However, having some options ready in case your first choice is unavailable is a good thing.
If you can't get something you really want, you can keep calling...daily, weekly, whatever. You can also go to the concierge desk when you check in at your resort and see whether there have been any cancellations.
