Why is one 340 connecting rod bronze color?

I reconditioned hundreds of rods in my 10 years as a machinist. I have personally honed the big ends of many rods where the bearing surface had copper all over it. I've pressed factory pistons off of rods and found the honed pin bores with copper in them.

It's done for size, trust me.

This post is about why the whole rod body is copper plated. I'm not saying that don't plate the big/little for clearance, but I kinda doubt they quote the whole thing for clearance..