Exactly, it must be a 30.06 sign and it has to be posted at all public entrances. If a sign is not posted with the EXACT language the law requires you can feel free to ignore it though. So going to a mall where there is a no weapons rule including firearms it has no force of law. You can be asked to leave but at this time it must be concealed and rendered completely unseeable so it shouldn't be a problem unless you have a big mouth.
As far as the OP, it is ALWAYS a good idea to read up on the state statutes when you travel. Some states give those signs the force of law and some don't. Other states will not allow you into stores that sell any alcohol even if it is for consumption off property.
When I travel I live by opencarry.org and handgunlaw.us and will even download a copy of the information from handgunlaw to carry with me for refference. It helps keep me safe and sane rather than second guessing something I can't remember after crossing state lines.
Speaking of Texas 30.06 signage, just read an article about the OC bill that has passed in Texas and businesses will be required to have 4 signs if they don't want people to carry. English and Spanish versions of 30.06 for concealed carry and English and Spanish versions of 30.07 for open carry.