Well I was looking at my Bespin Vader and wondering why the heck Hasbro would sculpt his chest inaccurately. You know, how his vest thing is over his chest/shoulder pads instead of under? It's only like that in A New Hope. I then remembered that this is Hasbro, and they like to save a buck or two. So I pulled out my 25th Anniversary Vader from the Final Duel two pack, and wouldn't you know it, my hunch was right! Bespin Vader's body is a slightly retooled version of 25th Anniversary Final Duel Vader! All they changed was the right shoulder cut. It also appears they recycled the right hand as well!
The recyclying of the hand is not that big a deal, but recycling the body was a mistake in my opinion.