Maybe. The pic below was found in an FCC filing for the Nintendo DS CTR. Sure, it's not a handheld in any way shape or form but it could be the prototype for one. In the middle of the board though is a 16x9 screen, which is different from all the DS variants out there. We're going to be getting some news of the
3DS at E3 so until, take a look of what could be the beginnings of the 3D handheld.
Source:
Engadget