Thanks
I can't believe I didn't think to use a magnet.
The color is NOT rust. At a distance, the frame color doesn't appear too differently colored than the barrel, but up close and under any kind of light, the VERY dark reddish brown frame color is obvious.
A conversion kit would probably cost as much as an all new SA gun, but from what I've read, the 8" barrel may be more accurate than that of regular single actions.