There's every likelihood that the 5S will incorporate tweaks to the finish of the phone now that they have learned from a year of manufacturing the iPhone 5. The housing shown could well just be a modified one from the iPhone 5 production line to prove the assembly of components would fit in the available space.
Minor changes to anodising etc may therefore be incorporated before we see the finished product.
Minor changes to anodising etc may therefore be incorporated before we see the finished product.