Ah, looks like Amelia changed her shirt (presumably after having spent the night somewhere).
In the first sequence, her short sleeves end just above the elbow. In the second sequence, she has long sleeves down to her wrists.
BINGO! Amelia never wears the same shirt two days in a row. That short-sleeved dark shirt with white piping she's wearing in the first boarding sequence is the shirt she was wearing on July 1st when they made the local test flight. The film up until 0:09 was taken on July 1st. I suspect the scene with the locals standing in front of the plane was also taken on the 1st because, in the second boarding sequence (long sleeves), the plane seems to be parked close to the hangar. I think the footage from 0.12 to the end was taken on July 2nd.
Note that in the second boarding sequence the engines are running. That seems strange to me. Why would she start the engines, leave the airplane, then re-enter the plane? She wants to conserve fuel. She needs to warm the oil before takeoff but there's plenty of time to do that during takeoff and pre-takeoff checks. Did somebody else start the engines for her?
I've stood on the wing of the Pensacola sort-of-replica that has the same cockpit hatch arrangement as NR16020. Climbing into that cockpit via the hatch is no mean feat. You're about six feet off the ground, standing very close to the leading edge of the wing and swinging your leg up into that hole. I sure as hell wouldn't want to do it with the prop turning about 3.5 feet away. Crazy.