The thing down there I would want is the car that Mr Carter purchased. Do you know how cool it would be to restore it and say you had the only car shipped on Titanic. I would be happy with the engine, transmission, brass trim and frame. If the movie was accurate it should be located in the bow, it should be complete minus the body work.
I am sure most, if any guns on board, were in luggage and there would be no way to locate them on the shipping manifest. Passengers had a substantial luggage allowance in those days.