is the grill not the same color as the body?

 

It looks a lot darker, even without the underlying black plastic showing through.
Barry

 

let's wait for the r170 members to chime in but if i recollect my slk 320, that part was painted black

 

Mine did that. I think it's quite common. All the ones I've seen are black and I just used a black aerosol. Gloss or Matt, it's up to you. Or choose any colour. The grill comes off easily for spraying.

 

My old one is grey and are close to mint condition.
The partnumber is 1708800785 but I can´t find the colorcode anywhere.

Clean it up and use plastic primer and then you can use any color you want.