via Eugene Moles' Facebook page:

Ventures Gene Moles trivia. My dad played and co-wrote two instrumentals on this album. " Gringo " and "Sunny River". My dad told me the story. Everyone was at the studio. But Nokie hadn't arrived yet. Him and his wife were still Christmas shopping. Producer Bob Reisdorff told my dad told my dad " You already know the guitar parts, lets go ahead and lay them down". So my dad played the guitar on these two songs. Those two songs were probably the first to have a Mosrite on a Venture album. Played by my dads 58'.

Dad and Nokie were very good friends then. Myself and Mom and dad stayed at Nokie's home.