I’m not sure about what ancoms believe but as a Marxist, I believe that communism is the natural stage that occurs after socialism, where there are no classes in which property and wealth are communally owned. So I’d say they’re pretty similar.
Plus, the hammer and sickle represents socialism with the hope of a future of communism. Not exactly, but the class struggle it actually represents relates to that. So I’m not sure why you would need to specify that.