this is the one I have, is an RCA collectors re-issue on 45, released in '49 or '50.
http://www.45cat.com/record/270149
i found this one on Decca,
http://www.45cat.com/record/940160 but I didn't know what recording that is, Whiteman's orchestra recorded it a number of times. The 1927 recording has Gershwin himself on piano, maybe the 1924 also. if another pianist is listed, its not a 1920s recording. there were also 1950's re-recordings, but those seem to be the more orchestrated version, not the original 1920's arrangement for jazz band.