[Cryptography] how to detect breakage -- lures etc.??

[Bob Wilson]

In the photograph of a KL-7 device, link embedded in
> https://www.cryptomuseum.com/crypto/usa/kl7

I am surprised by the "Confidential" markings on several labels. I would 
expect the device itself to be classified much more securely than that. 
I realize those labels are not official classification markings, but 
they might mislead someone into divulging details that were intended to 
be more highly ranked.
Or was all of the "more critical" stuff contained in removable parts 
such as rotors, with some scheme to make sure their higher 
classification was separately recognized?
Bob Wilson