The page at the link above indicates a 1948 recording and release. It seems to have been first recorded on film, whatever that means.
From the linked page:
Recorded February 3, 1948 at RCA Victor Studios, New York, Studios 1 and 2. Matrix & take numbers (in side order): D8VB-3643-1, D8VB-3644-2, D8VB-3645-1, D8VB-3646-1, D8VB-3647-1, D8VB-3648-1L.
Description: Dub from film: Orchestra, with banjo solo Victor BHC: "Elec. transferred from film."
Most of the following is paraphrased from "The Banjo On Record".
Rex Schepp was born Feb. 17 1897, in Greene Co. Indiana. He took up the banjo at the age of 7.
Shortly after the death of Vess L. Ossman Sr. in Dec. 1923, this virtuoso banjoist joined Vess Jr. and assumed the stage name Schepp Ossman to complete the remaining dates on “The Ossmans” father and son tour. They continued after as Ossman and Schepp, working in vaudeville and presentation houses until 1929, bringing Schepp to U.S. national attention.
He later made a major impact on the banjo world in premiering Nathan Shilkret’s banjo concerto “Serenade Rhapsodic “ with the Indianapolis Symphony Orchestra in 1944 and in recording a concert in 1948 of this piece and others with a symphony orchestra under Shilkret. On the album Schepp is heard playing both finger style and plectrum banjo.
Around this time he was considered one of the important banjoists in advancing the banjo in the 20th century. A young fellow named Earl Scruggs was about to change that. Schepp died in relative obscurity in Scottsdale, Arizona, May 4, 1988.