I have a Colt MKIV Series '70 Commemorative Government Model which I left in a soft holster, and needless to say I had some corrosion where the part of the pistol was not protected by the holster (bad error in judgement on my part, I know). I have cleaned-up the gun fairly well with rouge and a buffing wheel, but there is some pitting on the lock. My question is, can I order this one part or do I send it back to the manufacturer; and if I can procure the lock, any ideas on where I might find this? Thanx.