Actually, all of those parts are not all brown phosphate.
There are several different platings on the latch assembly.
I havea good pic of it, I just need to repost.
I used DX-579 to remove the rust and corrosion from my catch plate. I then cleaning it with soap and water and sprayed with protectant.
You can do the same, as long as it is not pitted. mine looked like it should be thrown away, so chances are good that yours will come out nice.
The catch loop has overspray
the lever is zinc DiChromate finish/natural silver chromate
The hood claw (mine) is black phosophate.
Dan