Jerry, some people take better care of their guns than others, and maybe this gun was used for ducks and geese and water migrated into the locks.
Here is a picture of an 1887 Quality 2, that I don't believe the locks were ever taken off. None of the screws were buggered in the least bit.The parts are still fine and I didn't do anything with them.
The internal parts of these guns from the factory were in the white except for the hardened parts.
As to what you should do, clean them like you did and give them the faintest bit of oil.