Been watching the last videos of Mr. Rojas Bazán (top class scratch modeller) and he says that the well known pic of the Stuka's factory is half mirrored (only the right half of the pic): you can count three hand holds on starboard when there was only two on that side. This led to a mistake that has been replicated many times, even in expensive scale models.
Edit: I'm not 100% sure about this, just starting a conversation.