Im not sure in your case because I dont have the part in hand, but has yours been repaired? Ive seen a lot of European doubles that have springs dovetailed into parts, mostly on sears and cocking levers. One way they could also achieve this is to make the part long, then bend the part in half creating the spring portion onto the cam, essentially making a very large bodied v spring. In the picture it looks like your part has been pieced together or repaired, or am I just not seeing it correctly?