Contact Don Schlickman for your repro parts, email dfsjpn at aol.com
He is going to need to know the date code of the pistol so he knows which firing you are seeking. Also, it sounds like you need the firing pin guide as well. Let him know if so. As for the firing pin spring if Don doesn't have one contact Wolf Springs. In fact if you plan on shooting it I would recommend you buy the whole Nambu spring set from Wolf Springs and replace the originals just so you know they work OK. You want Don Schlickman to do the work you seek.