REVENGE OF THE JEDI poster shown in one episode.

In the episode TREASURE OF THE MOKS, there are two posters (signs) shown that the Moks are hiding behind. One is for JAWS (in an earlier episode, the full billboard read JAWS 9, being this is set in the future)...

The other is for STAR WARS: REVENGE OF THE JEDI. This cartoon was made in 1980, three years before REVENGE OF THE JEDI even came out (thus changed to RETURN OF THE JEDI).

Since Lucas was good friends with creator Steve Gerber (he'd make Steve's character HOWARD THE DUCK into a horrible film), so I guess he got permission. But it's cool that there's a poster shown for REVENGE OF THE JEDI years before it was an actual movie.

Here's the image:

http://i281.photobucket.com/albums/kk236/fillerkish/thundarr.jpg