I hope the car actually has a 6L engine, and not just an E60 badge on the boot. Need some photos of the 6L engine decals on the radiator support, since there's none on the valve covers either. The car has an aftermarket big brake upgrade kit and what appear to be 18" Neez wheels, which are a nice bonus (assuming the brakes work properly).
There's an old thread about the grille upgrade, you can get OE MB parts from the W140 S600, but last I recall it was crazy expensive - like, hundreds of dollars. Something about the insert being NLA and having to buy the complete assembly maybe? Anyway, yes it's still plastic, but high quality plastic with stainless steel shiny strips. The cheap aftermarket ones have faux-chrome stickers, and actually look decent considering the low cost. The grille thread should have all the info you need.
EDIT - found the grille thread: https://www.500eboard.com/forums/showthread.php?t=5204
UPDATE: Auction description states 5.0L engine, not 6.0L. That was not in the original text. The was originally advertised as an E60 and later corrected to an E500; as seen in the URL of the auction.
This example is one of only 1,735 built for the 1994 model year, the penultimate year of production. Imported to Switzerland from Japan just over two years ago, this E500 is menacing in black over black leather. It appears as if a previous owner installed some tasteful updates to make it look like an E60 AMG, including fitting E60 badging to the boot lid, six-spoke AMG wheels and a dual exhaust at the rear. Japanese stickers found in the engine bay confirm its 5.0-litre engine capacity. Optional extras include
air conditioning, a sunroof and heated front seats.
Well regarded for their stately looks, bulletproof reliability and impressive performance, this is an excellent modern classic for any enthusiast looking to purchase their first collectable car.