dropped m 05B in the sea whilst climbing across some rocks. I did rinse it afterwards but never stripped it down. They are made of aluminium which is less prone to attack from salt but the fixings use steel components which will rust. Mine now definitely needs stripping down and thouroughly clening as its a bit sticky. But if you have only ever just stood it on a beach then you should only need to rinse off the bottom sections with fresh water and dry it.
If water has got inside the legs then you should strip it down and thouroughly wash clean.