Chives3300

Hey everyone. Looking for your guidance. Test drove a 2011 Sierra Denali about a week back and went to move forward with the purchase. They called me a few days later and said the engine started making noise when running through the shop. No noise was heard when I did the test drive. I know lifters are a major problem with AFM Motors, but since this is the L9H wondering is this too likely lifters & cam, or something else? 118k miles Video of tick: