My First 318 Rebuild

I'm not done with the heads, but I'm getting to the point where I might just have a shop go through them and put new guides and such in, it seems like that's a place where budget should be higher.
Anyways on to the bottom end, I cleaned up the conrods and got 3 that came out brown. It doesn't look like rust and it doesn't flake off or anything. I know nothing about the history of this engine so I'm not sure what I'm looking at.
Pictured is the one "normal color" one and the three brown ones

View attachment 1715906937

I believe the bronze plating means that the con rod has been reworked.

That is a strange set of con rods. A LOT of weight has been removed from the small end of three of them. But not the fourth one. Could be a big balancing problem. Steel crank motor?