Marxism pt 1: Marx the philosopher

Karl Marx's interest in philosophy took an early swerve into journalism, and he famously wrote that "philosophers have only interpreted the world - the point is to change it". On one hand he was a revolutionary who favoured getting his hands dirty in the muck of history over abstract theorising, but on the other hand he was also a man of ideas who engaged with many of the philosophers of his day, in particular Hegel. Was Marx himself a philosopher?