It is not a 2S coach!
It is a SLR (Sitting cum luggage van) coach, the one you see at the end of the train, in which reservation is made on the GS seats!
It will be packed with unreserved passengers and you'll have to fight a battle to claim your so-called reserved seat with people who's turn your claim down with a sarcastic giggle that railways can allot those seats to reserved passengers.