I can't say for sure, but I think I have heard that the cutoff time for lunch changes throughout the year - so your best bet would be to either check your confirmation email (if it says dinner, you're fine; if it says lunch, you will be getting the lunch menu, not the dinner menu), or if you don't have that, let us know more details about when your reservation is.
My guess is that is dinner time, but I can't say for sure. When we were there last month, 2:55pm was the last lunch reservation.