just as cars in many parts of the country used to rust bad and rot away
by being only 6 or 7 years old, and today seemingly go forever if not
scratched or dented the same thing has occured to other exposed steeel
devices.

The steel is better quality, and galavanized and protected better. all
this euuals little rust.

I would leave it uncovered, just placing anyting on top of the unit
then weighted down may lead to small scratches, turning into rust
later. wind can cause vibration leading to scratching the finish. baked
on enamel paints are so much better today too.

but hey if covering makes you happy go for it!