The guns were originally blued, essentially chemical rusted to give them a very deep blue to almost black surface appearance.
In military service they were never nickle plated, and never had gold plating on the hammers/triggers.
That was done years after it was made. It was, however, obviously done carefully because the stampings on it are still nice and crisp.
Value, I simply don't know. I'd say at least $200, but not nearly as much as one in original condition would bring.
As far as the "unconverted" statement you made earlier, after WWII, when many of these guns were brought to the United States, ammunition for them, a British round called the .455, simply wasn't available.
To make these guns shootable, the cylinders were modified so that they could be used with American ammunition that fired a similarly sized cartridge and bullet.
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza
Baby Jesus cries when the fat redneck doesn't have military-grade firepower.