The FBI is wrong, but this mistake comes from passing a statute that specifies certain conduct is legal. This is not the way penal statutes are written. Penal codes and statutes specify conduct that is prohibited, although exceptions to those prohibitions do identify conduct that does not come within the scope of the statute. In other words, everything not specifically prohibited by code or statute is legal.
The correct way for the FBI/NICS top evaluate Texas law is to look for a statute that prohibits the purchase of a firearm outside the State of Texas and they would find none.
I listed HB267 in the Bill Status report on the day it was filed, along with links to the text and legislative history.
Chas.
TPC §46.07 wrote:PC §46.07. INTERSTATE PURCHASE. A resident of this state may, if not otherwise precluded by law, purchase firearms, ammunition, reloading components, or firearm accessories in contiguous states.