Body panel materials

I know we barely have specs at this point but i wonder if the body panels will be steel, aluminum, plastic, or most likely some blend of all those. I DO think the all aluminum body on the F-150 is a plus especially because i live where they heavily salt the roads. i assume the F-150 Lightning has an all aluminum body but it's not enough to tip me in favor of that truck. i cancelled my Lightning reservation- i'm GM all the way lol.