That thing at the end of the firing pin spring does not appear to be the firing pin spring guide (No, 5 in the GPC diagram). That guide is a key to reassembly of the pistol, since it locks into the notch in the top of the slide so the slide can be pushed down into place on the frame. (FWIW, I hope you can get that gun back together; they are more than a little tricky.)
Jim