The buttons do have different designs on them - we got my Daughter the MK one at City Hall and the Epcot one at guest services in FW. She also got special treatments and Happy Birthdays from the CM's all day long. She got a Magical Moments certificate signed by all the princesses at our CRT breakfast that morning, as well as a little birthday cupcake. We did the Candlelight Processional package at Le Cellier that night - and the pastry chef decorated her dessert plate with Happy Birthday written in dark and white chocolate!
Didn't know they had buttons right at the resorts - next time we will have to check. She was already dying of embarrassment (She was turning 14!)