Ive done a few and I normally bolt in nylon plugs under caps to protect Journals. I like to be careful though... For the lifter bores I slide in plugs also. Im sure you could use some sort of barrier cream, that caustic wont eat too...(cant think of any) Im not going to say if dipping unprotected would effect things, I doubt it would really, but Im not saying either way. For nitric de-smut ALL steel items must be removed. Dont forget the spring perches, they can stick there un noticed sometimes.