I'm assuming that it's currently on a Carmax transfer from WA to VA? Typically with this it's at your cost to pay for the xfer. I'd start the conversation with Carmax, expressing your concern that they sold you a vehicle that wasn't produced for the US market without informing you. Explain that you might still be interested, but that you wouldn't have paid for the transfer had you known the undisclosed variance. The goal of that convo would be to get you off the hook for the cost but still give you the opportunity to inspect it and see if you have a real gem before opting out. I still think there's opportunity for an upside here. Just need to get your hands on it to see what you really have. Also I'd work to find out what 'foreign market' it may have come from so that you can start researching what parts might not be available here (i.e. interior trim bits, exhaust components, etc). You'll also want to figure out what the vehicle inspection process will be like when it comes time for registration. Here in Oregon, they plug in to your OBDII. Just wondering if the VIN doesn't come up with an emissions spec what that would look like when trying to get tags.
Again, this could be a really cool truck that came over with diplomat plates. Hope for the best, but hedge your bet for the worst.