Yes, it was Hal. And right after his stunning work on DON'T KNOCK THE TWIST!!
Buy that album DRMBARNUM. I just bought - for $1.99 plus s/h, an album of the Trapp Family singers singing the songs from THE SOUND OF MUSIC.
This album claims that the Von Trapps took their musical mentor Father Franz Wasner with them when they went over the Alps, and he lived with them for the rest of his life. That sure wasn't in the movie!