Are connecting rods/caps stamped from the factory by cylinder?

Sorry if the information is already out there somewhere. The FSM stated to mark them, but mine already are so just trying to confirm these stamps are from factory or this would tell me that this bottom half has already been gone through. I checked Lee's LT5 assembly post and used much of his info to get this far and will review again since I don' want to ask the same questions. His pics almost showed this being possible but the pic was blurry.

Thanks in advance.