Almost certainly didn't happen. 1st Annual Pennsylvania Old Time Mountain-Country Gospel-Bluegrass & Blues Folk Music Arts Festival.
ad: Bluegrass Unlimited 7, 11 (May 1973), p. 21;
ad: [contra] Bluegrass Unlimited 7, 12 (June 1973), p. 5;
ref: Flier, "Pennsylvania Old Time Mountain Country Gospel Bluegrass and Blues Folk Music Festival" [ca. 1973], Subseries 1.34, Pennsylvania, 1962-2002 and undated, Folder 506, Collection Number 30007, Southern Folklife Collection Festival Files, 1936-2019, Southern Folklife Collection at the Louis Round Wilson Special Collections Library, University of North Carolina, Chapel Hill, NC;