I haver a fondness for those stories too. Although I like a lot of the modern stuff, I do sometimes wonder if it is even possible for a hero to just fight a villain and stop him anymore without an emotional or moral crisis where he questions everything he is and does instead of just having an adventure.
To answer the main question, in most continuities, I think it was common knowledge that the Corps was alien in origin.
Power with Girl is better.
From GL #13--
https://jumbotronsdontwork.wordpress...en-lantern-13/