I'm not sure that's the case for the entire state, but you're probably right about most of it. I'm pretty sure that one of the big FIOS locations is in Texas.

*edit*
Yup, San Antonio is a big FIOS area, I believe, where they get a lot of the speed increases first. It also appears to be big in Dallas, of course, but also pops up in a few other locations like Houston and Austin. Pretty much the big cities like you'd expect:

http://www.dslreports.com/gmaps/fios