CZ made nice rifles in the 550 and 527: I've never owned or handled a 557. It always seemed the bluing was not very thick, and I was always diligent about the end of a damp day in the field to wipe down, and smear a film of hydraulic oil over the metal. The wood finish was always pretty good, so I would just wipe it down of moisture and sweat. But I was always this diligent with any rifle...
If you want, you can purchase bluing kits and thicken the blue... this is my second choice after just keeping it clean, and putting away properly. But coating over a blued surface won't work well, given that blue is literally a controlled oxidized surface and won't receive many surface coatings... it would have to be stripped... eww. Anyway, Birchwood Casey makes a nice cold blue kit: I've reblued some old, beat guns and several layers in, the bluing is beautiful and deep.