My stepson was not given a slip. He went for immigrant visa on January 23 2018 and he has been on administrative processing for almost 11 months. I petitioned for him in 2016. His dad has a pending interview at the embassy on Nov 21 2018. It’s that a reason for the delay?
You can track using application number at : Consular Electronic Application Center
It is hard to say, may or may not be…they do not disclose everything.