Nintendo was a bit confusing with their announcement of the Pokemon Volcanion distribution event in the US.
Although some literature had Volcanion datedfor "October 1," that was only for select GameStop locations, as the distribution cards hadn't been rolled out nationally yet -- plus, the codes themselves weren't even live until October 10. Now the day has come though, and you can go pick up your Volcanion, all the way after its leak in November of 2013.
I've spoken to multiple sources at GameStop that state if an employee requires you to pre-order to get Volcanion, that it's against store policy as there's nothing in the corporate memo that says that. Be firm and note that it's not the case, or better yet, just call your local stores until you find one that is willing to just give them out. If a store does run out, ask them to print the code on a receipt.