TexasCHLforum.com

To purchase a handgun, you must be a bona-fide resident of the state in which the purchase is made. You don't need a DL (nobody has to have a DL unless they're driving), but you must present proof of residency. A state-issued ID card that shows your address qualifies.

Someone recently reported that they weren't allowed to change their TX CHL address to an out-of-state residence until they sent a copy of their new state DL. I assume you could do the same with an ID card.