Here in the south, the giant flag in the truck bed would be a rebel flag. I've also seen one with a machine gun mounted on top of the cab. (Hopefully, non functional).
I've also seen a rebel flag bumper sticker on a Prius here in the south. Maybe he was saving the planet while promoting his southern heritage.
At least you're in the south. I'm infinitely more confused by midwesterners "showing their southern pride"
I don't think the wanna-be phenomenon knows regional boundaries.
I have a younger male relative, born and raised Canadian, who went through a bit of a Redneck Pride phase while he was in high school.
A city boy born and raised, my relative didn't like going out to visit other relatives on the farm. He never did learn to ride a horse or drive a tractor competently. But he was an extremely good shot, and liked to stomp around in a duster and a filthy cowboy hat. He was obsessed with the "Dukes of Hazzard" TV show, which was in its umpteenth set of reruns by the time he came along. He got in trouble with his parents for putting a rebel flag bumper sticker on his truck, and for racking up a list of traffic infractions as long as his arm.
Not long afterwards, my relative went through a construction worker phase (without an apprentice ticket), a biker phase (he didn't have a motorcycle and wasn't licensed to ride one, he just had the leathers and tats), and a law enforcement phase (security guard, since no PD would hire him). To my knowledge he hasn't yet gone through an Indian phase, so his Village People card isn't quite full.