The Russian media quote an unnamed defense industry source as saying that the Sarmat heavy ICBM will be eventually be deployed with two divisions - in Dombarovskiy and Uzhur. it is expected that the total of seven regiments with 46 missiles will be deployed (six missiles in a regiment plus one ten-missile regiment). The flight tests of the missile are not expected to begin before 2017 (so, the earlier report about the missile making an appearance in 2015 probably meant something else).
This is hardly surprising - only these two divisions have silos that are large enough to accommodate a large missile (although it's quite possible that the SS-19/SS-24 silos would have worked as well - Sarmat appears to be in the SS-19 rather than in SS-18 category). Together with the report about projected deployment of 30 rail-mobile missiles of the Barguzin system, the news about Sarmat shows that the concept of economies of scale generally eludes the Russian government - whatever are the alleged advantages of the new missile, it's hard to justify the development cost if you end up deploying only 46 of them. Yes, the Untied States ended up deploying 50 MX in silos in the 1980s, but the initial goal of the Peacekeeper program was 310 missiles. Sarmat probably won't end costing its weight in gold, but it will be an expensive missile.