Not necessarily. It's quite common to be able to express fluid (usually clear) from the nipples when estrogen levels are simply running high during or after a cycle..with no real gyno present.
If this situation is not dealt with, then it may develop into gyno. Now, if you are actually lactating then YES, you have very bad gyno to the point where you are able to produce milk. A person in this situation would likely have some obvious looking man boobs, but not always.
I think you should ask a Doc what black ooze means. I would guess that it is old blood and if you are expressing blood...seriously, go to the Dr as this can be bad.