Fastbolt - I will call S&W as others have advised, but I have a question about the dual-spring photo you posted. Since the inner spring is shorter than the outer spring, I assume it will butt up against the collar of the guide rod rather than butting up against the front of the slide, correct? Or put another way, the position of the springs in the left photo show top=rear and bottom=front, correct? Just want to be sure in case they send me the springs that I install them properly. BTW, I have a metal guide rod with a plastic plunger. Thanks to all for their input on this.