Another point seldom considered is that although, technically speaking, it's in the country illegally, who's gonna care? Not to be cheeky, but, yes, it's here in violation of Federal law, that's not really in question. But since (presumably) Florida has titled it, the authorities there must feel that it meets their State's legal requirements (discounting for the moment the possibility of deception on the part of the owner). The situation may represent a conflict between State laws and Federal laws. Happens all the time. Consider for example legalized weed--I can walk into a weed store here in Colorado and buy my choice of uber-refined pot. No problem. Totally legal in Colorado. But it remains a violation of Federal law. The Federal government (i.e. the F.B.I. and/or Justice Department) could, at their discretion, come to Colorado and arrest and prosecute me for the same action. But, were I to engage in such activity, I wouldn't reasonably fear that they would. The Federal government has chosen not to devote their crime-fighting resources to Colorado pot smokers. For now.
The question any potential buyer of this truck has to ask themselves is: "how likely is it that the Federal government will devote their crime-fighting resources to me?"
Most (if not all) of the cases of Federal seizure and destruction of illegally imported vehicles with which I'm familiar have involved unscrupulous dealers, intentionally flouting the law, deceiving US Customs and buyers. The Federal authorities get wind of it, go after the dealer, then go find all the vehicles. Too bad. So sad.
Will that be the case here? As a buyer, how much would you be willing to wager? That's what's at stake here.