Yes sir you can very much travel travel with gen ticket in UR coach of the train from SBC to kbl and can occupy your reserved berth at hindupur..
Also you can approach TTE and ask for your reserved berth to be allotted to you from SBC itself by paying difference fare unless its reserved for someone else till hindupur..Very high chances of it being empty till hindupur from SBC since its only around 2 1/2 hrs journey....