I picked up a couple of Donkey Kong 4 stack pcbs for repair, these are the type typically found in cocktail cabinets. The repairs weren't all that interesting typical stuff for DK boards (bad sockets, bad 8257 resulting in missing sprites, bad fujitsu TTL).
What I did find interesting is that one of them is a very rare and early TKG1 revision Japanese version that even predates the Radarscope boards that were converted to Donkey Kong.
I suspect there was a small run of boards made to put out on location to see how well the game performed before Nintendo invested too much money into the game. They wouldn't want another Radarscope on their hands where they got stuck with boards and cabinets they couldn't sell.
It has the original version of the game which has the levels in a different order, the ladder cheat and allows you to save long names during high score saving, the colour palette is also a little different. It is also a bit more standardized than later versions as it outputs regular video that isn't inverted and there's an on board amplifier for the audio which is usually on a pcb attached to the monitor.
The proms have hand written numbers, someone could argue that the proms are simply bad or from another game but as another board was found with the exact same 'off' colours (onecircuit on YT has a video) I think that confirms that originally Donkey Kong was released with these colours and Nintendo changed them later before the TKG2 boards were shipped.
It's not too obvious from these pictures but a lot of the colours are lighter shades, especially Donkey Kong who is a much darker brown in all other versions of the game.
