No need to travel in gs. Either try current resvn that day arnd 12 pm, if u dnt get a confrm ticket then take a gen ticket and pay fine to tte and get into s7.... This is ngp quota coach... U will find empty seat or jst ask the tte to allot u one. The train gets half vacant at kcg aftr which u will find a seat surely. I travelled lyk this on 28 oct while coming from nda ssb interview