Factual error: In the aerial shot over rural Britain near the beginning of the movie, there are two modern cars visible. Too new to be early 40's models.
Factual error: When the Petrox engineers dump Kong into the pit filled with chloroform they haven't knocked him out - they've killed him. Chloroform vapour is heavier than air so Kong is breathing it in a pretty pure form - and it is lethal in concentrations as low as 40,000 parts per million. In the time it would take to render a gorilla unconscious by this method, it would die. This ignores the fact that liquid chloroform is a severe irritant and a contact poison, and its breakdown products include phosgene and hydrogen chloride, both deadly poisons. They might as well save themselves some time and use that dinky little bulldozer to fill in the pit.
Factual error: In the scene where Cinderella is in her new room at the Prince's castle, the roses prominently displayed in the foreground are brightly coloured Hybrid Tea roses (the pointy ones) which were not bred until the early 20th Century. In the 1700s (panniered skirts and powdered hair) the roses would have been of looser formation, with softer colours, e.g pink or cream cabbage roses. (These roses also appear in later scenes.)
Factual error: When a Rear Admiral and Captain are walking together, the Captain's epaulets are the wrong way round. A cardinal sin in the Navy. (01:30:00)
Factual error: St. Ives is invited to sit in a Lincoln Continental. When he does, one of the owner's subordinates opens fire with a machine gun having what appears to be a 50-round clip. Problem is, he fires over a hundred rounds.