Help with Head Gasket selection
If it ran good why mess with it?
Those rods will be fine. Lots of theories about the copper color. Never heard about "dipping" before. They sure as hell aren't plated... I have two sets of resized and balanced 340 rods and they are a mix. I don't lose sleep over this stuff.
I'd be more concerned about those heads being machined properly, having the stems equal length...stuff like that.
But I've only been working in these things for 60 years...