If they had ported contra to the fds, the games, music, and sound effects would have been a bit different, especially if they used the fds extra sound channels and knowing Konami in the 80s they probably would have done that. This just uses the Nes version with an altered title screen. I very much doubt that Konami would have done that even for a mockup. I imagine that the game would have looked pretty similar to the Japanese cartridge version with some slight difference to save space. This is okay for a mockup, even if it's probably not a very accurate one.
If they had ported contra to the fds, the games, music, and sound effects would have been a bit different, especially if they used the fds extra sound channels and knowing Konami in the 80s they probably would have done that. This just uses the Nes version with an altered title screen. I very much doubt that Konami would have done that even for a mockup. I imagine that the game would have looked pretty similar to the Japanese cartridge version with some slight difference to save space. This is okay for a mockup, even if it's probably not a very accurate one.
So this prototype is similar IF NOT EXACTLY as the US version!
Where can I find it?
you can't. it's not real
FDS version doesn't make any sence.