I've had the exact same problem. I purchased a shorty clutch and regular brake lever from them (black with gold dials). After about 2 weeks you could really tell that they were fading. They went from a dark gold-ish gun metal color to straight gold in about a month. I'll admit tho my bike stays outside all the time because i live in an apartment, they still function great aside from looking like crap. I managed to get in contact with the2wheels and they wanted me to send them back...to China...for a replacement but I'm not going through all that. Anyone think it would be a good idea to get them powder coated or something of the sort?
Keep in mind, I took these pictures awhile ago, my levers are completely gold now. The first pic was taken right after i put them on.