I’ve heard that too.
In fact I’ve been told that his personality better fit that of the character he played in “A Face in the Crowd” - Larry “Lonesome” Rhodes.
By the way “A Face in the Crowd” is a great film. Well worth the time to watch !
Yes, I've heard for years that he was more like Lonesome Rhodes than Matlock. He was the kind of guy who makes a great murder victim on shows like Murder, She Wrote - a "beloved TV star" who really a jerk and is despised by the people he works with.