It’s actually a huge deal. Under the "Big Beautiful Bill," taxpayers can deduct up to $10,000 per year in auto loan interest on new, personal-use vehicles. However, that deduction requires final assembly in the United States (indicated by a VIN starting with 1, 4, or 5).
Because the Oakville Assembly Complex is in Canada, trucks built there will have a Canadian VIN (starts with 2). This means buyers of Oakville-built Super Duties will be completely ineligible for the federal auto loan interest deduction. Given the high price tag of these trucks and current loan rates, missing out on that deduction could cost an individual thousands of dollars.
(Note: This specific auto loan deduction phases out for single earners making over $100k and joint filers making over $200k. Also, if someone is buying the truck strictly for a business, they are largely unaffected, as businesses can generally write off loan interest and claim Section 179 depreciation regardless of the vehicle's country of origin).
To answer your question, "Do buyers get a choice of build site?"
Unfortunately, no. Customers cannot request or select which plant builds their vehicle when placing a custom order. Ford assigns the build location—whether that’s the Kentucky Truck Plant, Ohio Assembly, or eventually Oakville—based purely on trim level, specific configurations, and factory capacity at the time the truck is scheduled.
Once Oakville starts pumping out trucks, custom-ordering a Super Duty for personal use will become a game of "VIN roulette" if you are banking on that tax deduction. The only way to guarantee you get the tax break is to buy a truck directly off the dealer lot where you can verify the VIN starts with a 1, 4, or 5 before signing the paperwork.