It looks like they changed the guidelines for 2017 so it's less favorable for Camry which was the most American made vehicle the last two years. Now it's not even on the list.
http://www.marketwatch.com/story/these-are-the-most-american-made-cars-2017-06-26
For the first time over the index’s 11-year history, the considerations for making the list have been changed. The number of models meeting Cars.com’s original criteria has fallen due to the globalization of automobile manufacturing.
Using the new criteria, Cars.com scans for predominant U.S. sourcing for engines and transmissions, and high U.S. manufacturing jobs supported per vehicle [the American Automobile Labeling Act includes Canadian data within the U.S. “domestic” pool]. This year, the index deemphasizes overall sales — a factor that reflects the economic impact of a given model line — to focus on the domestic impact of a single buyer purchasing one model versus another. Ties are broken by giving the higher ranking to the heavier vehicle.
I think the Acadia is built in Lansing too. Not sure I would trust that at all.
-Geoff