George Henry Preble was aware of this flag and published an illustration of it, along with other Southern flags on plate IX of his monumental work "Origin and Progress of the Flag of the United States". See the link below. Preble's work on flag history was groundbreaking, but he was not error-free. On that same color plate, for example, he shows the Confederate Battle Flag as rectangular rather than the square ANV flag. His errors on some RevWar flag illustrations carried weight well into the 20th C as well.