Hi all! A rockwell hardness tester in Scale B or C. uses a diamond tip. It leaves a very sharp and small point indentation in the metal. Normally after the item has been machined and hardened. A Brinell hardness check uses more of a rounded (ball) point. A brinell check would be more of a check to the materials hardness before machining and hardening on a casting or forging, and the mark normally gets machined out. From my experience these look like dents that were caused by careless handling in the process. They more than likely mean nothing, and don't effect it's operation. But it's a new gun and if the customer doesn't like it, I see no reason not to get a replacement. Kudos to S&W for taking care of it as they did