Yes, I'm aware, you can buy FM 3-15.130 in a Kindle for $1.99, along with volumes of FM's. At one time many of the Intelligence Publications were classified, even publications from our spy days from the Cold War were classified, the Company Commander's Handbook, Counterintelligence Operations Techniques, Signals Intelligence, Human Intelligence, most all had basic FMs and sub-pubs which were classified. As you mentioned, classifications could be from OFUO to Confidential to Secret, Top Secret and further designations were not published as Field or Training Manuals. Such manuals were available at any Division level AG publications center,
At one time, part of my job was classifying documents, photographs and materials up to, including Secret. Classifications were assigned a declassification schedule as well, such as time sensitive periods when something became public knowledge or 20 years, 50 years, etc. So, we could have information from 50 years ago that was Secret to be unclassified today, like back in 1976. Thing is, operational TTPs today have been based upon operational developments of the past, actually from WWII, Korea and Viet Nam, today's operations didn't pop out of a computer last year.
I have no idea what information was compromised by the ex-employee, but I do know that taking her to court won't be a walk in the park, that a damage assessment will be warranted and verbal communications are hard to prove, I'm not defending this suspect but saying it's not going to be easy to prove treasonous acts.
Always Out Front, Lead The Way, Climb To Glory!