I had nearly all my BMW steering wheel airbag badges replaced because of this. They seem like a faded blue, and/or the yellowing of the badge. Strangely enough, all the replacement badges never changed color. My current E90M3 service records show the previous owner replaced it as well, and it looks like the outside roundel, dark blue/white ... perfect.
02 E39M5 | TiAg/Schwartz | Tubi Rumore | Ultimate Ti Pedals | E60 SSK | Jim Blanton 3.45 40/100% | Colby Alcantara | StrongStrut STB