Did they sell them as scrap or no sf97 available?
I bet they were listed as condition code "H7" which means unserviceable. A sf97 should be available if this is the case.
OP, You'll need a sf97 to register your trucks in TN. Go to your GL account page, click on "forms", open the sf97 form, fill it out, send them $60, and you'll get a sf97 in the mail. When you get the sf97 carry it along with your invoice to the county clerk's office. That should get you a title.
I have found out that some clerk offices will try and give you trouble with the way GL issues the sf97 (the sf97 will be in GL's name and it will be accompanied by a reassignment letter with your name on it). If this happens, call the state and have them call and inform the clerk's office on state regulations.