Though the vast majority of WT literature is available openly, there are indeed some things reserved for the privileged. You need to know where to look to find these, and the common JW has never seen them.
An example: The Elders handbook:
"SHEPHERD THE FLOCK OF GOD"
As to secret teachings, let me give you this perspective. Take a look at their initial study book, What does the Bible Really Teach?. Read what they teach to the initiate. The chapter on Jesus, for example (ch 4). If you read it, you might conclude their view of Jesus is not so different from a main stream Christian. However, the chapter doesn't go into explaining that the "pre-existant" Jesus, is Michael an archangel. Nor does it explain that after Jesus' human death, Jesus was "re-created" back into the spirit-creature Michael.
I could go on, but your concern is most definitely warranted. In my conversations and studies with them thus far, I would say ALL their doctrines are so complex and labyrinthine that they cannot possibly explain one single doctrine in one document alone. In other words, all their doctrines are kept to some degree from the initiate, the general public, and from new converts.