Replacement space grey screws for bottom case

I know this sounds a bit obvious, but check out eBay

try looking up the screws for that model, with the colour in the name, and if that fails, just look up that type of screw, and seeif any that are the right colour come up

if all fails, get any screw that fits, pop into your local hardware store, and get them to mix up a tiny tin of paint of that exact colour(they have machines that scan the paint and give you the colour code), and then paint the screws with that!