I actually already in April did a video about both a Gold and Grey sim card trays for the next iPhone, the iPhone 5S :) It's time you you start getting that I am living on the edge when it comes to hot news ;)
So yeah, it really looks like the iPhone 5S will come in 4 different colors, White, Black, Gold (Champagne) and Gray. Apple is really going for different colors this year.
See my video from April here:
The image above compares it to the gold iPhone 5S nanoSIM tray and the white iPhone 5 tray.Source: Gray SIM card tray for iPhone 5S points to a fourth color option - GSMArena.com news
The gray SIM tray is too dark for the white iPhone and too light for the black iPhone. It's possible that Apple will tweak one of the two standard flavors of its next iPhone but it's also possible that the company is trying out a fourth color.