No doubt in my mind the gun has gold washed flutes, that have obviously been cleaned to the point the majority of the wash is gone. The scratch through the gold wash is obvious in this photo. Even the gold inlay on the upper right V is getting faint by the looks of it. But every photo you posted clearly shows gold washed flutes, condition of the finish and the various levels of finish lost. My question now would be who did the gold wash. I'd bet Colt. But that info is not on the Colt letter. I'd ask Paul @ Archives again.
You may not care about the gold wash or silver tarnish but the next owner might. At that level of Colt collecting you can likely bet on the fact the details will matter.
This guns gets more interesting every time you post a good photo.