Really?!?! I thought they would never open for Kenny Rogers since he thought one of Roger's most successful songs (Coward of the County, was an attack on the Gatlin Brothers, since the "bad guys" in that song are name the Gatlin brothers. Rogers did not write the song, but I am sure he plays it every time.
I saw them in San Antonio. Don’t remember the year.
Kenny Rogers / THE GATLIN BROTHERS / THE RIGHTEOUS BROTHERS
May 16, 1984 T.H. Barton Coliseum Little Rock, Arkansas, United States
https://www.concertarchives.org/concerts/kenny-rogers-the-gatlin-brothers-the-righteous-brothers
Coward of the County came out at the same time the Gatlin Brothers formed as a group so it is not possible the song referred to them.