And thus my comment earlier about being an R2 builder and nothing truly being "screen accurate", as in most movies things change, sometimes from film to film (if there are sequels), and other times scene to scene. The trick is to be as close to what people expect to see. I've had Lucasfilm, Disney, and even fellow R2 builders all comment on how mine is more "movie" accurate than most others, and that's only because I looked at how R2 looked in different scenes in the different films, then made the decision to stick mostly to the first one, A New Hope, but there are a few bits that are more Empire. A few builders kept one of the panels on the back of R2 silver, as there was one scene (ONE SCENE!!) where they forgot to paint that panel...

Only we know what's what for the most part. No one complains that the guy who plays Santa at the mall, really isn't.