Some things need to be clarified here regarding the crew statements. it appears the names are correct with the statements...
1 Stripe: Third officer/Trainee
2 Stripes: Second officer/Flight engineer, Second officer is the member of an aircraft's flight crew who monitors and operates its complex aircraft systems.
3 Stripes: First officer, First officer is the second pilot (also referred to as the co-pilot) of an aircraft. Assist the captain through flight planning and updating communication and flight mechanisms.
4 Stripes: Captain, The one ultimately in charge of the safety and operations of the flight.
Only the time is not correct in the document....
Here are some "alternate facts" for the stripes in the 1971 time frame.
1 Stripe - Head of the cabin crew.
2 Stripes - Flight Engineer and possibly also the Navigator and Radio Operator if they were required for the specific aircraft operation.
3 Stripes - Rated Co-Pilot but not a rated Captain.
4 Stripes - Rated Captain.
There was no such thing as a "trainee" cockpit rating.
On extended flights exceeding the 8 hours flying time per day permitted by FAA Regulations, two rated Captains would be required and maybe additional Rated Co-Pilots. A Rated Captain could also act as a Co-Pilot.
Anderson had three stripes and was acting as a Flight Engineer on the hijacked airliner. Those three stripes meant that he was a Rated Co-Pilot on some NWA aircraft which was probably also the 727. In the early days of the jet age, an entry path for pilots to secure an airline position was to go through a Flight Engineer course and then get hired as a Flight Engineer. When a pilot slot opened up, they could then move up to a Co-Pilot position. I understand that Anderson was a military trained jet pilot and this would be one way to work himself into a pilots position. In the 1971 era, cockpit crew seniority numbers ruled just about ever thing and Anderson was probably a low number on the Co-Pilot seniority list at the time of the hijacking. Since the hijacking took place during the airline travel off season, he probably elected to continue flying as a Flight Engineer rather than being furloughed (which were notorious in that time period). Of course, he knocked off the lowest number on the Flight Engineer seniority list. But that is the way the system worked back then.