The version on the "right" is a copy, plain and simple, the "shadow bars" have nothing to do with the source being digitally modified. The original workprint - as is well established - was a 70mm print. At least the version is actually on DVD, after all it's only die-hard fans who care about, no one else wants nor needs to see that version of the film. I'd suspect that when the 70mm print was copied to 35mm, for some reason it was cropped at the top and bottom, and that process damaged the film somewhat resulting in the shadow bars. They could well have pulled both version from the same film under that understanding since the "shadow bars" showed them where the film was cropped when it was copied to 35mm. Or they might have known exactly how it was copied and done that on the few frames you see that are not colour-corrected and are heavily cropped. That's just a guess; remember people said the work-print was grainy in the theaters, so I don't think they used the best copying process they could when they showed it in theaters...