This Chronicles themed DS skin is official, and could be found at Game Stop stores around the time of the release of the game. As you can see here, it's 9.99 regular retail. The main art used is from the box art itself, which has Sonic & Shade on the clouded/night background. The interior just seems 'dark blue' but is likely to have some type of pattern or logo on it and not be plain.
Additional Info
- Region: America