The USSR never entered an Oympiad before the war, and indeed even let Dubrovnik 1950 (Tito's Yugoslavia) go by before finally taking the plunge at Helsinki 1952.
It would be very misleading to start thinking of a USSR team in terms of Keres, Flohr, Lilienthal, Mikenas - four of the strongest players in the world at the time - for these four would have been playing against the USSR, leading the independent nations Estonia, Czechoslovakia, Hungary and Lithuania respectively.
To pick a hypothetical team we must go first to the USSR Championships. The 1934 Championship would have given 1. Levenfish, 2. Rabinovich, 3. Bogatyrchuk, 4. Ryumin, 5. Alatortsev. The 1937 Championship would have given 1. Levenfish, 2. Konstantinopolsky, 3. Ragozin, 4. Makagonov, 5. Belevenetz. There was also, of course, Botvinnik! Although he did not enter either of these national championships, he had amply proved himself internationally.
Probably the strongest team available to the USSR at the time of the Stockholm Olympiad would have been 1. Botvinnik, 2. Levenfish, with Konstantinopolsky, Rabinovich and Ragozin (in whatever order) making up the five. Tho two top boards would have been a match for anybody, but whether the other three could have matched the sustained power of Kashdan, Marshall and Horowitz is very much open to doubt.
W. H. Cozens, The Lost Olympiad, p. 219.