Cab to frame bolt access holes filled with water. advice please.

I have recently fixed a leak in the rear wall pressure vent and the third break light... and the window.
I removed the plastic coverings to the access holes for the cab to frame bolts so as not to damage them when dealing with rust spots. Both of the access areas were completely filled with water.

I assume that is a bad thing so I have a couple questions:

- are these bolts actually securing the cab to the frame? I am only guessing.
- is there an important reason the plastic covers / seals are not water tight?
- should I be treating that area with something or just leave it after I dry it out?

There is not really a lot of rust inside the access area. Much less than I would have expected being as this is not a new leak.

I have to wonder if everyone who has had a leak in the back of the cab does not have the same issue and is just not aware of it.

Thanks.

here is a pic of what they look like now:

 

Spray some Woolwax, Fluid Film, or Blaster Surface Shield on them. It may smell for a bit but it goes away. You should be able to get any of these at an auto store or hardware store.

 

I have heard about lanolin making its way into the automotive industry. I think I will go with that.
My father used to shear sheep and his hands would be covered in the stuff.. I quite like the smell. I will go with the woolwax and hope the smell is the same.

Thanks!