Yeah they did.
MIGHTY GUNVOLT MINI-FAQ
If I donít have a 3DS, is it possible to get Mighty Gunvolt for some other system?
Sorry, but no. Mighty Gunvolt is only available for the 3DS.
If I live outside North America, is it possible to get a code for my region?
Sorry but we can only offer everyone North American 3DS eShop codes. We realize backers come from all over the world, and we very much value our fans from other countries, but unfortunately region-free codes were not an option, so we picked the region where the majority of our backers hailed from.
I hit the double whammy by living outside US and not having a 3DS, so I just gave my code away.