The late Harold B. Simpson, an expert on Hood's Texas Brigade, listed Hugh T. Tillery as a casualty at Gettysburg. Most of us assumed that Mr. Simpson was correct. However, my own subsequent research indicated that Tillery was killed at Chickamauga on September 20, 1863. I corresponded extensively with Mr. Simpson before his death, when I was researching the 3rd Arkansas Infantry, and was informed that he had based his Gettysburg casualty list partially on some assumptions and misinterpretations. That was one of the very few errors I have found in his landmark four-volume history of Hood's Texas Brigade. Which shows, I guess, that even the best and brightest of us can make an occasional mistake, which makes dullards like me feel a little better.
Anyway, Private Tillery was reported present for duty on the August 31, 1863, muster roll (nearly two months after Gettysburg), and was killed in action some 20 days later at Chickamauga.