If the Epcot 30th pins are handled anything like the MK 40th anniversary, they will only be sold at Epcot.
For the 40th, lines formed early and they handed out wrist bands before the park even opened. Based on the color wrist band, there were certain hours you could line up. Basically, the color guaranteed what you would be able to get. There was a chance of leftovers from the previous group, but it wasn't guaranteed.
Also, for the MK 40th, they only sold pins at one location. (It wasn't even a store location).
Watch the various Disney websites and forums, for the MK 40th, information literally came out 1-2 days in advance and changed the day before.