I looked at what imslp has, unless there's some mistake, it's less than a page of music.Still, playing in Carnegie Hall... But still, from what I can tell you need to learn a few gimmicks about the organ, the part hardly needs learning.
Quantum -- I think that your link refers to the original instrument. At the present time I believe that the instrument is a Rodgers 550 -- unless they've gone and changed it again...