When Jim Chee was opening a film camera to remove the film cartridge, one can see that the film wasn't rewound ("8" is visible through the counter window). Removing the cartridge from the camera before the film was fully rewound ruins the photo due to the accidental exposure. However, this type of cartridge is fully sealed, so other than the possibility of a small amount of light leakage, no film exposure would occur.
When searching for bomb fragments, Henry can be seen using an army angle-head flashlight. it has switchguards which were not added and issued until the mid 70's.