The engine number is stamped on the top of the metal spacer between the oil filter adaptor, (that the oil hoses to the cooler connect to), and the engine block. Its easiest read from the passengers side of the cab.
The chassis number is stamped into the chassis rail on the passenger side, almost directly behind the upper mounting bracket for the muffler. It is just behind and below the winch rope guide rollers. It will start with 6X6 and be in inch high letters, but may be hard to see as they could have a few layers of paint over them. You can just make it out in the pic below. No cab on this truck so it was easy to find.
