Something I just thought I'd add about those coaches, just in case anyone else has the same thing happen and wants a permanent fix for the model: If you can access the actual 3D mesh itself and get it into a 3D editor, you want to select all the surfaces and 'flip normals' which basically flips all the surfaces around. Those models were created inside out, so you're basically looking at the back of all the faces, making them appear invisible.
Keep up the great work, Scott!
Keep up the great work, Scott!