The engine oil pan was crushed during shipment, necessitating replacement. Whether that was the fault of the shipper or the seller, we don’t know. After finally locating a new replacement pan, the old one was removed. This engine does not look like it could have over 100 hours. Most likely, it appears that whatever HMMWV this powertrain came out of, it was likely a 6.2 that was upgraded to the 6.5NA and then sent for scrapping.
Update (Dec. 15, 2018): As we had to remove the timing cover to replace the water pump, we were afforded another view into the internals of the engine:
As visible, this is clearly a fresh engine. Not even the paint marks have discolored from oil and heat, and the Loctite 518 (or similar) had not been washed away. There is a slight amount of rust visible at the top of the upper timing gear caused by ambient air entering through the oil fill, but this should be considered normal, especially on an engine obtained from a de-mil.