I suspect that most early colts actually had a charcoal blue finish with nitre blued screws. I've played around with the charcoal blueing process over the last year and it is capable of giving that wet ink black blue finish that collectors lust over, assuming you do the pre-polish right to begin with. The problem is that it looks pretty darn close to a high class caustic blue, at least close enough so most people would never know the difference which is kind of annoying in a sense.
Every rust blue that I have ever done, or seen has had a slight matt finish to them, not a lot, but certainly not shiny and it in no way reflects light like a modern blue finish does. If you think about it this makes since because there is an etching reaction the surface during the rusting process. Bivins thought this might be why the rust blue finish looks more blue than black due to the fact that there was more surface area reflecting light than was true in a highly polished modern blue (or charcoal blue for that matter).
As far as the original finish on those rifles if it was blued it would likely have been either a charcoal or rust blue and my vote would be toward the rust blue.