Couple of silly S3/4 newbie questions…

What are the two chrome finish discs/fasteners either side if the filler cap? Are these for a hood cover to clip into? If so does that mean a car with them fitted would have been supplied with a cover, or do MMC fit them as standard?

Also, I’m looking to get a basic Becker (with ipod connection) head unit in my next Aero, which color illumination would suit the dash better, Orange or Green?

Thanks in advance! cheers
Matt