The USSR was created in 1922 so the first one for sure cannot be from 1918. The cited first article of the constitution belongs to the constitution of 1936. The image clearly attributes it to the constitution (by small font below the phrase it says "from the constitution of the Soviet Union" and the entire phrase is in the quotes. So my guess is that the first one is from 1936-1937 (because later citing the first article of the constitution would look too trivial, but the same year the constitution was adopted it's ok).
Regarding the second one, it is clearly from post-WWII era. Note the ribbon bar on the chest of the man which suggests he is a war veteran. Also note that the girl has a badge of the Komsomol similar to this:
This design was adopted in 1944, so the second picture is definitely from a post-WW2 period, but not later than 1952 due to the name of the party VKP(b). I guess it is from 1950-1952.