Mine (metal ver.) has a inspector seal, reporting JAN '93.
The BIOS reports (C) 1993 indeed.
Asked NeoBomberman about the wood he own, still need to check, but it is likely made before.
I should also check some flyer copyright, but my conclusion is that the kidney joystick was made initially for the Deck Unit in ~92/93, and only after one year, recycled for the ngcd project.
Edit: