Not true. Lariats are also built at the Kansas City plant. However, I assume it may be only Lariat's of a certain configuration ... ie no PowerBoosts, etc.
Here's the window sticker of a KAN-built Lariat that was built on 2/7 and shipped just last week ... on its way to Virginia.
https://www.windowsticker.forddirect.com/windowsticker.pdf?vin=1FTFW1E50NKD34849