These axles have been outside for 2 years.  They have been covered until about 3 months ago or so.   I have no way to know for sure but I don't think that you would have a problem with water getting in.  And no I don't think that anything is rusted to bad.

With regards to the rust, everything was taken off with a torch.  If you look at the pics the control arms are still attached and they were cut from the vehicle.  So I don't think that anything will be more rusted than if you were to take it off a vehicle.

Hope that helps.