They could replace the skin with foam board, but all that weight savings would just let them reduce the battery to save more on the manufacturing costs.
FYI, it only weighs about 400lbs more than the F150 Lightning, so the skin probably doesn't add much weight over a traditional truck skin. The four wheel steering tech and glass roof probably add more.
It's funny, the world was excited for basically a teched out Toyota Tundra with shitloads of battery. The designers were ready to build that, and they could have kept literally everything else the same (steer by wire, steel skin, glass, bed cover, etc) and everyone would have been happy.
Even looking weird people were excited for it.
But then they deleted half the range and doubled the price and ::pikachu face:: everyone hates it.
Sure, musk was the reason it looks weird, but I'd be willing to bet he's 100% the reason for those other things too, because they likely had to cut weight and size to make it's weird look physical possible.
(I'd still buy it if it had 500+ range)
In the U.S., you can build rockets all day long, they cannot be guided.
https://www.law.cornell.edu/uscode/text/18/2332g
You'd have to convince the feds it was never designed to be a weapon. Good luck with that.
And then, one day, I got in.