Importation of Canadian-manufactured trucks

We’re considering purchasing Canadian-manufactured trucks in Canada, and importing them to the United States. If these trucks had been manufactured in the U.S., their sale would be subject to Section 4051 tax (FET). Will our sale of these Canadian-manufactured trucks in the U.S. trigger FET? If so, would FET still be triggered if we used these trucks in our business rather than sold them? Also, does it matter if these trucks were new or used in Canada before we purchased and imported them to the U.S.?