Replacement may not be necicary. Most bearings (if not all) are bi metal bearings. Some which contain brone or copper. My guess is that it wore through causing the discoloring. Just check rod length and have them magnafluxed.
I think what giddyup is trying to say is that there's probably nothing wrong with your connecting rods; but that your connecting rod BEARINGS may need replacing. Sounds like you need to have someone (a good automotive machine shop perhaps) help you assess the rotating assembly's integrity.