I had the opportunity to call and talk to Todd at Turnbull earlier today and get some info. on my gun. Although he didn't have notes on specific work done to the gun, it was in fact there for work in the past.
He indicated that they use only the bone charcoal method of coloration and that it provides little protection, if any at all, from rust. He further described how guns, other than Parkers, are given a protective clear coat on the receiver. His idea was to thoroughly wipe the gun clean after shooting to prevent any rust formation....
He also indicated the gun would show rust equally on both the receiver and the blued bbls. There was little interest in the fact that the barrels were not affected. So, I will try the various products everyone was kind enough to share. Probably find these products on the web? Thanks again everyone, great bunch of guys and knowledge base. Brian