I'd sell a kidney to see that. I've also read that there's so much alternate footage of ANH that you can construct a completely different movie. That'd be an extra worth buying the big set for.

Those unfamiliar with the practices of movie production companies during the silent era might not realize that the creation of multiple complete, yet different, negatives was common practice before the conversion to talking pictures. Studios made film prints directly from the original camera negative. Duplication stock intended to copy a negative to make an identical negative, did not give satisfactory picture quality. Even special effects, split-screens, double-exposures and dissolves were done “in the camera.” Even during the late 1890s, a short film made two years earlier by the Edison Company was so popular that the negative wore out servicing print orders, so the actors were called back to film the story anew. Even in 1914, D.W. Griffith shot just one take of each shot for his mammoth epic The Birth of a Nation. The wear on the negative, early in the run — necessitating that some scenes be recopied from the better prints for lack of any better source — may have convinced the better-financed filmmakers that it was a good idea to film a second usable take on each shot, unless the film was deemed of limited appeal. Chaplin made of policy of setting aside alternate takes. Major productions in the United States were filmed under policies calling for multiple good takes on each shot, so that a complete negative comprised of alternate takes could be shipped to Europe, eliminating the need for the primary negative to be shipped back and forth across seas as demand increased for new prints...

...[Fritz] Lang prepared three negatives of Metropolis.

So if John Williams went ahead and scored the scene, and those cues in that brief segment of music sound like they are timed perfectly with some film edits, we can probably assume that the entire scene was filmed and remains somewhere on a Lucasfilm shelf.

Paul Harrison, master of [Elstree Props, a prop house that worked on the Star Wars films], alerted me to this page on his site where he has actual photos of the hero prop that was created for this scene. Interestingly enough, he claims that not only was this shot but it was cut from the film and then lost.