In the Spanky and the Our Gang version, the song also appears on an album in a long unedited version, including the group warming up their harmonies in the beginning, as well as an extended ending, where the sounds of a tape machine rolling back, plus the sounds of the group's joking until the fade is completed, causing one of the members to state that they need to get a new producer, resulting in laughter. This version lasted over 6 minutes in length.
"Sunday Mornin'" was listed as one of the "102 most performed songs in the BMI repertoire during 1968".
In 1968, Marie Laforêt released "Et Si Je T'Aime", a French version of "Sunday Mornin'" with lyrics by Michel Jourdan. She also recorded "E se ti amo", a version with Italian lyrics by Daniele Pace. A Hebrew version, "'Bo Habayta" (Come Home), with lyrics by Avinoam Koren was released in 1969 by Israeli singer Shula Chen, on her album Yours, Shula Chen. Chen's version became synonymous with Tnuvacottage cheese after being used in a commercial for the product.