True. "Among those present were such figures as Sergei Rachmaninoff, Fritz Kreisler, Leopold Stokowski, Walter Damrosch, Jascha Heifetz, Leopold Damrosch, Alma Gluck, Mary Garden, Amelita Galli-Curci, Moritz Rosenthal and Efrem Zimbalist. The influence of the Rhapsody in Blue on Rachmaninoff, who had done little composing since leaving his native Russia six years earlier, was to be heard in his Fourth Piano Concerto, whose premiere he gave with Stokowski in 1926." Rhapsody in Blue: About the Work
There are also two passages in Rachmaninov’s “Rhapsody on a Theme of Paganini” that sound like Gershwin and feel like Gershwin on the fingers.