Can't help much with the question except total teardown then clean and oil, clean and oil.
For the future though...
My guns are kept in a fire proof safe but it's not waterproof.
Every time a hurricane has come close since Rita I have done this...Make up long bags from the Food Saver rolls. Slide your long guns in and pull a vacuum on them with the machine, then back in the safe. I take the bolts out of the bolt actions, the charging handles out of the semi auto shotguns and the scopes off and store them in large Zip lock bags...don't want to pull a vac on the scopes. The bags are marked with the guns "Name" and rolled up and saved for reuse.
For those that don't have a machine you could probably still use the wide Food saver rolls to make up extra long bags and just roll up and seal the ends with Duct tape. After the "Event" though I would take the guns out of the bag in case there is any moisture in them.
I have some that still have a good seal since Rita.
Frank