NVIDIA will reportedly not offer a reference design, so all models that ship on launch date will be custom-design versions. However, the rumor mill indicates all boards will have the same frequency (1607MHz base, 1683MHz Boost) because NVIDIA is not allowing the frequency to be changed.
There are two versions of the rumor though. One source claims overclocking will not be possible, while the other suggests it will be possible to manually overclock the GeForce GTX 1070 Ti.