Honest question. Were they installed afterwards? Do pics from the 1940s exist?
Discussion
There's plenty of information on it.
The first photos were taken by the Soviets after the winter show cleared.
The site has been modified for propaganda reasons.
The "gas chamber" was clearly smaller rooms knocked into one, with holes added to the roof where the "gas" was dropped in. The leaky inward opening doors, the fake chimney, the list goes on.
It's an insult to German engineering, a typical Soviet "half assed" job.
The chamber I visited years ago didn't have lights installed and they dropped the gas from the side.