I have been given two Singer treadle sewing machines in cabinets. One works fine. The other one is missing the needle clamp. I am trying to find out where to get one, but I don't understand how to tell what model mine is. It has a long spindle-type bobbin, and the number on the right hand side front of the machine is D544403. I can't find any other numbers on the machine. Any advice on how to proceed from here? Please help!