Bidspirit auction | Soviet Union Stamps of 1924-40

Soviet Union Stamps of 1924-40 - 1937, 20th Anniversary of the Bolshevik Revolution in Russia, pre-printed souvenir envelope produced by International Historical Cover Committee (probably located in the US), bearing three commemorative stamps (5k Subway seems to be pre-cancelled) tied by Moscow ''7.11.37'' ds, VF and very unusual item, Est. $150-$200, Sc. #551, 569, C50