The picture below is reportedly of the iPhone 5S' display assembly as it goes down the assembly line in a factory in China. While we have no way of verifying whether or not this image is legit, if it is, then it would appear that the device's face remains unchanged. This is what we would expect for an 'S' model iPhone. S models generally feature updated optics, processors, and internals, while maintaining the same case.
The image below is reportedly of the glass for the display assemblies. This also demonstrates that the iPhone 5S should feature a very similar body design, if not the same. Of course, as with all rumors, take this with a grain of salt.