Joe S, I don't know any Hawken flint deniers. Everybody figures they made some flint rifles.
There are, as I understand, zero intact flint J&S Hawken "mountain rifles" or "plains rifles". The prestnce of the Smithsonian Hawken rifle which was once flint but is a late rifle has no bearing on this fact.
Most folks' interest in Hawken flint rifles is around having an early flint Hawken rifle. But we don't know what they looked like because no surviving examples exist. Now it's easy to make a reasonable guess. But that is a guess and when kit or parts sets makers put out what is a "flint Hawken" kit or parts set they don't tell anyone, "this is a very reasonable guess about what an early flint Hawken rifle would look like."
Next question: in addition to Ashley's big rifle, how many flint plains or mountain rifles did they make that went west? Their production versus repair and other work in the early years was lower.
So it is easy to deflect the real questions by stating correctly, "Of COURSE there were flint Hawken rifles."
For those interested in re-creating one, or understanding their prevalence among the mountain men, there is not much to go on but good guesses. I have no problem with good guesses. I just like to call them good guesses.