It's interesting you bring up the frizzen spring. I had my hands on a Dolep screw barrel pistol for a period of time and it had a standard style frizzen spring. With this being the case, it extended a little past the front of the frame. At some point, the standard became a spring arrangement like this pistol has. I would hazzard a guess that this pistol is a little later than the Dolep mentioned previously. My guess would be 1695 or later for this pistol, but I guess it's kind of splitting hairs.
