When I got my first set done, AP tyres in Rotherham they had a set in direct from Lexus Sheffield that they had just done so it was just a case of asking for mine doing the same as those.
The second set I has done were done anthracite which at the time assumed would be the same as the Lexus grey colour only to find that they were in fact darker in colour. The Lexus grey colour is a lighter metallic colour and in my opinion better, the photos I have in my gallery are all the the Lexus grey colour.
I assume Lexus grey is gun metal grey but not 100%, might be worth checking with Lexus to ask them what colour they ask for when they get wheels refurbished.