a quick lookup
from
http://www.alternatewars.com/WW3/WW3_Documents/DARPA/DARPA_II_PENAIDS.htm
Due to their large warheads, the Soviets had less need for accuracy and used blunt-nosed RVs for some time. Cf.. ABRES 1962-ASMS 1984, TRW, Inc., 1985. p. 15 and p. 2.
How about we actually
look at the RVs to see how this claim checks out? Here's the warhead for the Atlas-D, the archetypical blunt nose RV.
Since the early single warhead missiles didn't need aerodynamic nosecones for multiple RVs like the later MIRVed missiles did, their RVs tended to be pretty obviously mounted. You can pretty clearly pick out the RV on the nose of this Atlas.
This is good, as I can't really find any pictures of these early Soviet RV's without the rest of their missile. Now here's the silo-version of the R-16 (SS-7 Mod 2 in the NATO designation, R-16U in Soviet), with most of the stages cutaway to focus on the RV. Tell me: are you seriously claiming that is the same shape as the Atlas up there? Because to me, it looks pretty clearly like a bicone with a frustrum that is pretty much the standard on ICBM RV's these days.
By comparison, here is the RV for the W76 which is up on modern US Minutemen-III. As can be figured out at a glance, it's basically identical in shape to the R-16's RV and radically different from that of the Atlas's. The only real difference is size (the W76 is about 2/3rds the height of a human being while the R-16s RV is around twice the height).
Now with the SS-6/R-7... well, things get odd there. The R-7's RV
as tested in 1957-58 is on the right there and it's pretty obviously a bicone-with-frustrum design. The R-7
as deployed (which the Soviets designated as the R-7A, while NATO doesn't appear to have made any distinction between the two) however is on the left and it actually looks like something of a halfway cross between the R-16s bicone and the Atlas's blunt nose. Not entirely sure why that happened, but apparently it increased the payload while saving weight?