I received both of Kino's new Keaton blu-ray offerings today, and I can confirm that the organ score on the Steamboat Bill, Jr disc is Gaylord Carter's legendary score (arguably one of the finest recorded scores for a silent) and not the Lee Erwin score as credited on the back cover art and menu screen. I guess the confusion came about from Lee Erwin's score being featured on the older blu-ray (I assume that the Erwin track is owned by Cohen). Truth be told, I am quite pleased over this discovery.
Never cry over spilt milk, because it may have been poisoned. - W.C. Fields