MAMEWorld Forums - EmuChat - Contra Arcade PCB video colors

This video:

https://www.youtube.com/watch?v=yopInlfN7Zc

claims to show a real Contra PCB running. Compared to MAME, the colors of the protagonists' hair at the title screen, and the stones in the first level, are brown instead of gray. Yet the grays in level 2 are still gray, so it's not just a strangely-adjusted monitor:

https://www.youtube.com/watch?v=rTwADzl8stM

Is this a hacked bootleg/clone that I am unaware of (I have tried all that -listclones gave me)? It could not be an emulation issue, as people would have noticed before, and another video shows it like MAME does: https://www.youtube.com/watch?v=zK3Ggn5pCnA