There is a development forum for this, and this has nothing to do with iOS.
That said, the answer is yes, it will work. The sandbox rules are this:
- You must use a sandbox on your Mac app.
- You must store anything your app needs in the sandbox, or use the given Open/Save APIs to let the user open/save files outside of your sandbox.
This will do nothing to prevent you from downloading files from your Mac app to play, and saving them inside your sandbox for caching/etc.