"Dedicated to the Granite Mountain Hotshots and all the firefighters who saved the historic buildings in the Valles Caldera National Preserve"
This is the only season the finale is episode 13. Every other season only has 10 episodes.
Charles S. Dutton (Detective Fales) and Lee Tergesen (Ed Gorski) were both on OZ. Even though they both have recurring roles, this is the first episode they are both on Longmire at the same time.
Just before Walt talks to Branch outside the Sheriff's Office Branch there is a shot of a Movie Theatre showing two made up films called A Serpent's Tooth and Minden 2. This is a possible foreshadow of what is to come in season 3; A Serpent's tooth is a quote from Shakespeare's King Lear, with the full quote being "How sharper than a serpent's tooth it is to have a thankless child!" Literal meaning - it is especially painful to raise an ungrateful child. A possible reference to Barlow and Branch's upcoming relationship.
And Minden was a battle during the 7 years war (1759), suggesting a battle that is to come for Branch.