The picture happens to come from the same place where we saw the gold Apple iPhone 5S last week, so there is some reason to believe that the SIM card tray is genuine. The Apple iPhone originally was available in black and then white was added to the lineup with the Apple iPhone 3G. Gold would be the first new color added since then, and it could be that gunmetal accompanies gold.
Gunmetal is defined as being a dark gray color. And while we cast a skeptical eye on the report, we should leave a little room to be open minded considering the strong possibility that we will see a gold model introduced this year. Apple hasn't officially announced the date when it will unveil its new Apple iPhone lineup, but that is expected to be September 10th.
source: Ascii.jp (translated) via SlashGear