they really are man, and yes he appears in a very few- I believe he is actually in one or two of the last ones Barks did? there was certainly one DT comic that Don Rosa wrote the script for that involved time travel (Back in Time for a Dime) but on the whole the two worlds are just that, two different worlds that happen to have the same cast. Think multiverse. They did/do have independent Ducktales and Darkwing comics though so you can always check those out!