Well, 'Waco' is indeed a true story. It's drawn from the historical events that took place during that time, although some creative liberties might have been taken for the sake of dramatization.
I'm not sure specifically which 'ronnie mathis story' you are referring to. There could be many people named Ronnie Mathis, and without more context, it's difficult to say.
Yes, it was real. The Waco Kid's story was part of the broader lore of the American West. There were real - life outlaws and gunfighters during that era, and the Waco Kid was among those whose tales were told and retold. His exploits were likely exaggerated over time, as often happens with such stories, but there was an original kernel of truth to his existence. People in the West at that time had to be tough and resourceful, and the Waco Kid represented that spirit in the stories that emerged.
The Waco Kid is purely fictional. It's not drawn from real-life events or people. Writers and creators often come up with such characters and stories to captivate and engage audiences through their creativity.