I don't know how special you are expecting the restaurant's reaction to be, but if you are looking for them to do something other than congratulate you, like bring you a special dessert, they might do that, or they might not. If you want a guarantee on that, you would probably need to arrange for that yourself, and pay for it.
Calling the restaurant directly won't help, and WDW-DINE won't be able to assist on this. If you'd like to order a cake, there's a cake thread with the number for the cake hotline. You can buy a celebration cake at the restaurant, but it wont' be personalized.
For birthdays, anniversies, and other celebrations,
no restaurant/resort is that much better than another.
1)
Acknowledgment is a matter of the CM's personal initiative.
. . . depends upon how much they like you as a guest
. . . depends if they feel like doing anything special today
. . . depends upon the phase of the moon
2) CM's can do a lot, or they can do nothing at all.
. . . they are under no obligation to give goodies or even acknowledge, or
. . . they can go way overboard and give lots of gifts to a guest
3) The CM's have a lot of leeway of things to do or not do for you.
4) Have your anniversary-birthday-celebration noted on the ressie and ADR's.
5) Some of the things a CM can do
for free are
. . . decorate table with Mickey confetti
. . . best table location
. . . special personalized menu
. . . character-autographed birthday cards
. . . balloons
. . . wine or champagne or Shirley Temples
. . . appetizers or desserts
. . . cakes
. . . cupcake with candle (almost always available for the asking)
. . . placemats autographed by characters
. . . free appy pr free dessert
. . . room full of balloons and/or flowers
. . . fruit basket or wine basket in hotel room
I booked it online and filled in the add a celebration bit. Is it enough to just do that or would it better to speak with someone on the phone? Any experience with adding a celebration to your ADRs? Thanks! 
