The passport stamps for Germany are written in English, which would have been quite uncommon at the time. Additionally, the typeface is a modern style, which would not have been used.
The 1931 Koenig, while listening to Jemma's long-winded scientific analysis, asks her to "cut to the chase." Although the phrase "cut to the chase" did not come into usage among the general public until later, it originated with silent movie filmmakers. Since the type of people that visited speakeasies in New York were often actors, directors, etc., Koenig could have heard the phrase many times before 1931.
Koenig says the speakeasy doesn't have any entrance except the front door. Even if the illegal establishment doesn't have an emergency escape, they would have to load the alcohol in somehow other than the password-protected front and only door.