I don't know what resource you are relying on for all of your culinary misinformation jennerose - but Texas is NOT the only place in the USA that makes Guacamole - either at home, in restaurants or commercially!!!
Although it might be more commonly found in the states that border Mexico ... Guacamole is only a condiment, a dip - it is popular all across the US. And, 95% of the avacado production in the US is in southern California - which would preclude Texas as being the only source for Guacamole.
In addition to being served as a "dip" for corn chips, potato chips, or pita bread ... it is also used as a condiment on salads, sandwiches and "burgers".
"It ain't what you don't know that gets you in trouble. It's what you know for sure that just ain't so." - Mark Twain