ROTJ was the only one I saw at the cinema.
I remember those as exciting days, from the first pictures that appeared in newspapers. I was on holiday in France at the time and my dad had picked up an English language paper. And there in the movie section was a photo of an evil looking creature called 'Bib Fortuna' !
Later, Debenhams the department store had built a big Star Wars themed toy section that you could walk into. Over the doorway a TV was continually playing video highlights from the film. One day Darth Vader himself came to Debenhams to do a signing.
It really was Darth Vader, because he signed himself as such. So presumably just a guy in a suit and not Dave Prowse.