I just got a used G19 gen 3 (early model), which is my first Glock. It is a retired LEO gun, but other than some holster wear, it's a good gun. The recoil spring has been replaced already. Since the gun is a few years old and I don't know how may rounds this gun has fired, should there be any hurry to replace the firing pin (& spring)? Any favorite places to get parts online?