When Marty asks Rust to meet him at a bar, the scenery in the background changes from just grass to grass and trees depending on the shot.
When we see a handful of change before Maggie picks up Marty's phone you can see a cent with the shield on the reverse, which wasn't minted for the first time until 2010, when this episode took place in 2002.
Reverend Theriot tells Rust he found pictures of naked children by accidentally knocking over a book in the school's library. He says the book was a volume by "Telios De Lorca, 12th century Franciscan mystic". The Franciscan order wasn't founded until the 13th century.
When Marty is watching TV in 2002, he guesses that the show the family is watching is called Dumb Blondes in Cracker Country, but The Simple Life didn't premier until 2003.
When Marty sits down to a TV dinner with his family (set in 2002) he says he's 'just happy to be sitting here with three beautiful women watching- what is this? Dumb blondes in cracker country?' This is a reference to The Simple Life (2003), a reality show starring Paris Hilton and Nicole Richie that didn't air until December 3, 2003.
When Cohle is interviewing the woman suspected of killing her babies he is smoking Camel "Blue" cigarettes. They were called Camel "Lights" until 2009/2010. The interview was set in 2002.
At the very end of the episode, Rust asks Marty to go to a bar. When he goes back into the truck, the camera mount at the back of the truck can clearly be seen in a reflection on the right for the rest of the shot.