The movie is based on three of the original comic books: The Crab with the Golden Claws (1941), The Secret of the Unicorn (1943), and Red Rackham's Treasure(1944). It has won many awards including the Golden Globe award for best animation. It has awesome graphics and characters look as if they are original people.
Even if you have seen the cartoon serial for this episode it won't create a problem as this is something much more than a 20 min. cartoon episode.