Every title of an episode has always involved a color (which was always red before Red John was finally killed). While this title "Byzantium" may seem to not fit, it is an actual color name, used for one of the many shades of dark purple.
Wild hogs in Texas are considered a nuisance animal and so cannot be "poached". Anyone can hunt them at anytime without a license as long as they have consent from the land owner.
Toni Trucks (who guest-starred in this episode as the park ranger) and A.J. Buckley (who guest-starred in the last episode as one of the thieves/hostage-takers) went on to star together in Seal Team as co-workers and lovers.
Alex Saxon, who guest stars as Gabriel Osbourne in this episode, would later appear as a cast regular on Robin Tunney's follow up series "The Fix".
Agent Cho, known as a good reader during the series, has the book "The Idiot/Dostoyevski".