New Old Stock (NOS) Genuine Detroit Diesel Exhaust Rocker Arm & Roller Assembly, part # R23538247, for Series 60 engines (12.7L and 14L models) in buses, trucks, and heavy-duty diesel vehicles. Made OEM part is unused, in original sealed plastic packaging with minor box shelf wear. Metal parts like gears have grease on them, this is not rust as some pictures my seem to show. HIGH-VALUE / SERIALIZED DIESEL PART? Clear evidence of part swapping or fraud? Honest mistakes or fitment questions? Happy to work it out!