
These rumors suggested that Samsung has begun working on a super-premium series of flagship phones called the Galaxy F, and it might just be that the SM-G900F is the super-premium variant of the Galaxy S5. This premium version could be the one Samsung is ordering all those metal chassis for, while keeping the faux leather back for the standard Galaxy S5 (SM-G900S), and also the one on which Samsung would use its rumored fingerprint technology.
Of course, this is just speculation, so you're free to make of it what you will. A market launch of the Galaxy S5 is still a couple of months away, and I'm sure we'll see more details leak in the coming days to back up or refute the rumors and leaks that have run rampant lately.