In case you were wondering about GFZ:
Penal Code 46.035 Unlawful Carrying of Handgun By License Holder
(6) on the premises of a church, synagogue, or other established place of religious worship.
http://www.handgunlaw.us/states/texas.pdf
It's illegal to carry in a church in TX?
It's up to the particular church. If they post the signs, it's illegal to cc or oc or both (depending on which sign(s) is/are postes. Signs hold the weight of the law in Texas.