Not entirely. In fact, one of the main "insights" brought by Stalinism was the rejection of the necessity of the Marxist international revolution in favor of Socialism in One Country.
Not entirely. Socialism in one country was a temporary measure since the world revolution did not take on in the 1920s. The way that measure worked was to build up military and political power to force the revolution even if some countries were not progressive enough to do it on their own. Hence the slogan. Hence the USSR forcing "revolutions" all over the world.