On The Howdy Doody Show what only words Goodbye kids were saved for the final show?

You're remembering correctly! The phrase "Goodbye kids" was only used on the final episode of "The Howdy Doody Show".

This was done to emphasize the show's ending and give the audience a sense of closure.

Although "Howdy Doody" and "The Howdy Doody Show" are now iconic, they did not use the phrase "Goodbye kids" at the end of every episode.