from https://www.reddit.com/r/StarWars/comments/8qo1j8/revenge_of_the_jedi_poster_1982/
Are those the original colours or are they fan made? I’ve seen this poster before, but only as a B&W sketch.
According to this - http://www.starwarsarchives.com/dt_gallery/1983-posters/ - it may well be an official poster - by Drew Struzan.
Some cool posters on that site - be careful - you could spend a few hours there… 😃