The U.K. hardly has much to brag about either, we're nowhere near America-level in terms of TPCi giving a rat's arse about us, though thankfully due to English being our language we're not as forgotten as you guys
I don't think it will be exclusive, there will be a release of it for America. If it was a stamped promo like the TRU one you just got it could be exclusive, but being part of the XY promo set I'm positive it won't be
I held off on ordering the box as I wanted to know how the shiny Magikarp would be released (I'm in the UK) and didn't notice the small print saying it was included in the box. It does seem really odd that they wouldn't put it alongside the Gyarados promo, although thanks to this article drawing...