Your 'blueprints' are just decal sheets for a 1:24th scale model and they have a copyright date of 1999. Also, the text isn't Russian; It looks Slavic to me.
I'm sure you know this but third-party decal sheets are common to scale modelers:Example
But your question about Soviet 'reverse engineering' is interesting. I'm sure it was very possible that examples of P-51s fell into Soviet hands before the end of WWII, especially during the operations over Romania, Hungary, Czechloslavakia, etc. and as the Western and Eastern Allies converged upon Berlin in the final days. But I doubt that replicating the Mustang was was ever a high priority for the Soviets. The P-51D didn't arrive for combat until mid-1944 and by that time the Soviets were fielding 'home grown' fighters that were just as good or perhaps even better--at least for the kind of air war they were engaged in with the Luftwaffe.
The United States didn't really use the P-51 (aka F-51 after 1947) for very long after the war either; by the early 1950s fighter jets were becoming increasingly operational and even Air National Guard units that had been using WWII vintage F-51s and F-47s were transitioning to new F-86s and other production jets.
Regardless, I'm sure there are thousands of pages of data about P-51s in Soviet archives that was collected during the war and afterwards. I have no doubt about that at all.
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