It is accurate, but keep in mind that is data up to 2005 and published in 2008. That right about the time TPWD was coming up with its mountain lion protocol for reported sightings (ie, what requires a site visit, for a couple years I had the glorious distinction of the most investigations in the state). What I do remember about the Brazos cat is that it was from really early in the reporting, so early 80's. Beyond that, I don't have a clue. I also remember hearing somewhere along the way that a couple of the East Texas cats had a potential link to captivity.
Circa '99, there was a lot of excitement in Washington County too, and long story short, it was a German Sheppard.
Honestly, about the only thing that can be said about the mountain lion population is that we have two genetically different populations (and they don't intermingle all that much). The general belief is that the population is stable to slightly increasing, but from a scientific standpoint, that is a swag.