These ideas might still have relevance in many developing countries. So there are important and major differences between anarchists and Marxists. Marx was no libertarian and took a very deterministic view of history and class struggle. His disciples from Lenin to Stalin and Mao picked up and expanded on Marx's bad ideas to come up with their theories of 'the party before all else', the rationale for their dictatorships. On the other hand Marx and Engels have unfairly been demonised by a lot of anarchists.
Most anarchists accept the much of the economic analysis put forward in 'Capital'.
These ideas are a synthesis putting together the results of hundreds of years of research and struggle. As such they are not, properly speaking, the property of Marxists. One can accept a materialist method of analysis and Marx's critique of capitalism without accepting the politics of Marx and Engels. These ideas are not the property of theorists, either Marxist or Anarchist. They really belong to all the workers of the world and it is our job to spread them.