The visual of St. John's, Newfoundland shows a modern high-voltage power line across the hillside which probably didn't exist in 1927. Also WW2 American Air Force base Fort Pepperell is visible in the background. It wasn't constructed until 1941.
The real Charles Lindbergh was never allowed on the set of the film. Jimmy Stewart said if he showed up, all the cast would walk off. Lindbergh was hated for his pre-WW2 actives with Nazi Germany.