Being the victim of any crime sucks- "WE" (productive, hard-working and honest members of society) bust our rear-ends to provide for our families, remain productive and positive members of society and get the job done- The "others" (those that choose to steal, lie, cheat, refuse to work, etc) will continue to take advantage and plunder a system that allows them to. Having said that, (and I'm sure this has already been posted by others in the thread), if you can "prove" those seats are yours (either a build sheet, vin, some other ID that ties those seats to your vehicle) and you reported them stolen to the local Police, you could probably get them back and help to end this bone-head's "business" of selling stolen parts on Craigslist as a revenue stream and he'd be forced to either get a real job or some other variance. Reporting the theft and reporting your discovery will help, hopefully Dallas PD Detectives can sting this ****** and get your (and anyone else's stuff back), especially if you can prove those are the seats out of your truck.
Sadly, typically the only ones who suffer for crime such as this are the victim, their family and the persons who "do the right thing" who are in-convenienced and forced to jump through multiple hoops for little to no satisfaction. I'm cynical, I'll be the first to admit it- 26+ years as a cop did it to me, but I'm also very aware of the impact this type of thing has, time-wise, money-wise and the overall feelings of being stolen from- For that, I'm sorry.
I will say that while Karma isn't fast or instant in most cases, it IS RELENTLESS.... just takes a while to circle back around sometimes. Hang in there- it sucks, but try not to let the "shit-birds" ruin your trip. I know that's easier said than done. Good luck, be safe-