Did you get it right?
Everything on this old post-office counter fits the period except one item.

The Answer
The correct answer is: The modern thermal shipping label on the parcel..
Here is why
- Scan the stamps, envelopes, scale, twine, and rubber stamp.
- The parcel label uses a modern thermal-print format.
- That label is the only item out of place.
Why people miss it
It is attached to a period-looking parcel, so the eye groups it with the surrounding postal tools.
What answer did you get before checking?