As far as I understand the legs are aluminum. Want to know best way to clean them, they seem to pitted and rust forms on the tops where they mount. Second question is would switching to stainless hardware stop this rusting?
You can clean the legs with steel wool or you can try an aluminum polish (sometimes used to clean the lid dampers). If the screws/nuts are rusting, then switching to stainless may help. Just be aware and even stainless will develop rust when exposed to the high temps of a grill...witness the stainless Flavorizer bars in a Weber gasser that develop rust when exposed to high direct heat.