Hi,
I travelled in this train once in the year 2015. We had a reservation from SBC to MYS. Noticed that most of the train was emptied at SBC itself and the coach in which we had booking was around 50% vacant. There were many MST holders/unreserved passengers also (one of such person was occupying our seat but vacated after we told that we have reservation). In spite of this, the coach was 50% empty.
I am not sure about booking counter but there must be one at SBC.