Judy Harrington Diamond (SLHS '59) had the answer in her scrapbook! We think the recordings I posted a few days ago were the first two numbers played at the Region Band Contest in Texas City on April 26 & 27, 1957. She also saved an amusing picture, too. Here's what Judy said,
"The photo of Johnelle Pauswang Cooper, Pam Helmcamp Clark and yours truly is from a different marching competition. (Apparently we were trying to get permission to go to either the ladies room or the concession stand. lol)"
I'm glad we've got that incident on film.