Like I said, I would try to get it to shoot again just to see how it would handle it. I have seen AK's fired until the wood forends start on fire and machine guns shoot until the barrels are red hot but they keep on chugging along. Unsafe as they are with all that discolored metal by your statement. I used to work with a bunch of ME's and did learn one important thing - they are never wrong, just ask them.
Mechanical Engineers build weapons... Other Engineers build targets. They should know.
We are talking about a 44 revolver here, that is actually somewhat a high pressure round where heat treatment of the steels is important to the strength/integrity of the weapon. I work with heated metals all the time, and conduct piping strength test pre and post welding. I also am involved with our fire/building/mechanical codes and pressure vessls. This revolver is definately heat affected and it had some exposure far beyond that which was intended. The typical house fire burns at right around 1900° for at least ten minutes. There is no doubt. Heat affected. To what degree?
Edit to add.... Looking at the photos again, it is also apparent that the fire could have changed the alloy of the steel with carbon from the fire and recrystalized the metal. It is not the same steel that left S&W.
My vision, face and hand, and that of those standing around me is of paramount importance. Ever had a double charged round, or a overpressure round go off? I have. This revolver may hang together and shoot most ammo well, with no effect. It's just that once in awhile I know an overpressure that happens, even in factory ammo. My life, eyes, hands, and vison are worth much more to me than trying to save a few dollars by cleaning up a revolver where there is question. I'd certainly kick anybodys rear end for firing this hunk of metal in the lane next to me and not allowing me to vacate. MY Sight and body parts are far more valuable to me than a questionable firearm.
Further, in twenty years when you are dead and gone, your daughter and her husbancd may go out and shoot it. Are you willing to take that chance with their lives? With your pretty little grandaughter standing right there? How about twenty years after that with your young greatgrandson standing there learning to shoot? If you are, you are a much poorer man than I.
It is incomprehensible to me that anyone would consider restoring a firarm such as this!