The answer really depends on the lighting conditions.
Inside my home, my K-22 Outdoorsman looks jet black.
But outside, under direct sunlight (high noon) it appears less black, as seen in the above pics.
And under overcast, it looks even grayer, as seen in this pic of my Registered Magnum from the same era. If you put it and the K-22 Outdoorsman side by side under the same lighting, the finishes look identical.
So your interpretation of "black" is going to have a lot to do with lighting conditions, and if you are comparing to photos, the exposure settings can vary from what you see visually with your eye.
Having said that, if unfaded, the original factory blueing was quite black back in the day. If you are wondering about a reblue, you need to check for wear around engraving and lettering, screw holes, and look for obvious wear vs blueing finish. If the blueing is very fresh looking, then the color casing on the hammer and trigger should be pretty vivid as well. Faded color casing with fresh blueing should set off alarms to have a closer look. Under no circumstances should the hammer and trigger be blued. The first places blueing gets worn is at the muzzle and on the backstrap, plus the cylinder line and the front edge of the cylinder. The ejector rod will quickly pick up wear markings as well.
