Mr DuBose,

The 3rd Arkansas Infantry Regiment was certainly with Robertson's Texas Brigade at Gettysburg. At Gettysburg, the Brigade was made up of the 3rd Arkansas, the 1st , 4th and 5th Texas Regiments. As far as the 3rd Arkansas being part of the "Texas Brigade" ( ANV variety) throughout the entire war, I don't know. I know that a Georgia regiment was part of the Texas Brigade for a while. This Board has plenty of experts on the Texas Brigade( I'm not one of them) . I'm sure someone can tell you which units belonged to the ANV Texas Brigade during its colorful and outstanding history. Of course, any of the late Col. Simpson's books could tell you the answer.
Good hunting , Craig