Whenever a new device is landing or being prepared for an arrival, there are normally a number of details which come through first. While specs and images are the big headliner aspects of leaked or uncovered information, what is far more typically early on, is the uncovering of their model numbers. Although, the model numbers do not often provide any firm details on what the relative device will bring, they can provide some information on what likely range of devices the new handset will belong too.
For instance, thanks to an IMEI database listing, it is now known that Samsung are working on two new handsets. These come with the model numbers SM-G928S and SM-N920F. Now, although, on their own the numbers do not provide any meaningful conclusions, they do, when you factor in Samsung's other model numbers. For instance, the Samsung Galaxy S6 goes by the model number SM-G920F (as well as other derivatives of this). Therefore, it seems same safe to assume that the recently uncovered SM-G928S is going to be a variant of the Galaxy S6. Likewise, the Galaxy Note 4 comes with the model number SM-N910W (for the U.S. anyway). Therefore, it also seems likely that the SM-N920F will be the Galaxy Note 5.
Interestingly, sources for Sammobile (via link below) state that the new variant of the Galaxy S6 is internally being referred to as "Project Zen". Likewise, the codename being used for the Galaxy Note 5 is "Project Noble". Unfortunately, neither the model numbers nor the codenames do provide any details on what to expect with either variant or device and also do not provide any firm details on when either can be expected. Although, it is worth pointing out that in addition to the main model numbers, various regional and carrier model numbers are also starting to emerge now for both devices. Therefore as well as the main model number for the Galaxy S6 variant (aka Zen), the model numbers SM-G928A and SM-G928V have been spotted which are likely for AT&T and Verizon. While the SM-G928S is likely to be for South Korea and the SM-G928F for Europe. In terms of the Note 5 (aka Noble), the additional noted model numbers include the SM-N920F (again for Europe), SM-N920S (again for South Korea), SM-N920K (also likely South Korea) and the SM-N920A and SM-N920V, which are likely to be AT&T and Verizon respectively