It must be. The amount of detail is incredible, and even trying to extract data from the before picture, it doesn't come close to what you see in the newly processed image.

My attempt: https://i.imgur.com/QZDDEB5.png

I keep seeing a small dog in the helmet.

Looking at it "correctly" the man's image is obvious.

I enjoy image-art for this 'eye of the observer' opportunity.

Absolute least they did is to rescan original film with newer type of scanning process/device into higher resolution and bit depth „digital negative”. You cannot replicate that from low quality jpeg image.

Of course because you don't have access to the original data.

Imagine:

1. Film -> Method 1 -> Photo #1

2. Film -> Method 2 -> Photo #2

Instead you tried:

3. Photo #1 -> Method 3 -> Photo #2

Which instead gives you a badly edited Photo #1. You don't have the source code, so to speak.