According to the original video of Footage Farm, which Vasilevsky's address included, Vasilevsky just says only about North Atlantic Treaty(북대서양 조약 - as a Korean, I can hear the commentary), which concluded in april 1949, not NATO.
I compared the slogans posted on Gum of this parade with 1949, 1950, 1951, 1952 may day parades', and I found that only 1949's exactly matches.
![](https://i.ytimg.com/vi/q2byJfkgO54/mqdefault.jpg)