Gold and silver iPhone 5s will be very hard to find tomorrow

As opposed to the iPhone 5c, consumers were unable to place preorders for the iPhone 5s. The ostensible reason being that supply will be very constrained initially. As we’ve noted earlier, this is likely due to what are rumored to be low yields on the iPhone 5s’ fingerpring authorization sensor. While yields have reportedly improved, the pool of iPhone 5s devices at launch will be relatively small….
Yoni Heisler’s blog