I'm 99.9999999% sure there's no engines in any of those cars. No engine, not a vehicle. No code issues. Same thing as those truck bed or car trunk couches you run across in man caves now and then. Furniture, art, whatever, but it isn't a "vehicle" for code purposes, IMO.
Obviously, if I'm wrong and it has an engine and a fuel tank and can be driven out of that spot, then all of your above replies are legit. But I don't think Gibbs let him take any of those cars home with $100,000 dollar engines in them....