I never heard about AutoNation until this story, but their reputation just went kablooey now.
There is a fairly significant scam market for buying used vehicles in the USA with counterfeit checks. The vehicles get shipped overseas where they locals aren’t so particular about having a valid title history.
Normally they do this with higher-end collector cars, but I guess they can buy a beater truck too.
They are a nationwide dealer network.
But, while they should have removed the business decal, I wouldn't be so sure they sold the truck to someone questionable.
The owner says he traded the truck 3 years ago. Look closely at the inspection and registration stickers: they are dated 2014. Someone has renewed the registration in the past year.
It would be interesting to do a title search on the truck, but you would need a VIN. It wouldn't be expensive: http://www.add123.com/.