Here's a Presley Demo Acetate with a Proud Pedigree. Roy C. Bennett's Own Autographed Demo Acetate and Sheet Music of the Song Relax.
Relax, written by Roy C. Bennett and Sid Tepper, is one of the team's 42 songs recorded by The King. Elvis sang Relax in the movie It Happened at the World's Fair. The 78-rpm demo acetate of the song and its sheet music are autographed by Roy C. Bennett.
A demo (demonstration recording) of a song is made to persuade an artist to record that song.
When Elvis heard this demo, cut in a leading New York recording studio by top professional musicians, he approved Relax for It Happened at the World's Fair. The acetate is in very good condition. The sheet music is in very good condition, with some creases at the top of the cover page.
You can find it on eBay searching for itemnumber "7528063953".