Of course the idea is not to follow everything up to the smallest detail, but to establish a plausible environment.
So, for one tiny example, this is a spoiler-free document that we have in the game:
[img]{STEAM_CLAN_IMAGE}/36101081/384ab536f9cad959c3d653ea5ad29e9d3d02d348.png[/img]
And here is a real Nazi-era document that I took a photo of at Sachsenhausen concentration camp memorial:
[img]{STEAM_CLAN_IMAGE}/36101081/b9c219027b485e3a633517b8f4413ba120d88fbf.jpg[/img]
Hopefully this increased attention to details will let you better understand the atmosphere of those perilous times.
Please stay tuned for more info that is coming really soon.