Jspy
The color of the gun is like none of the finishes you mention.
When you put boron carbide over polished stainless it provides a glossy, almost clear grey.
I had a Browning MK III done in boron carbide from the same source. Mine came out a satin grey due to the metal being covered which was a forged steel. But the barrel, which was polished steel, came out the same color as ArmySon's 1911.