Apparently, barrels on originals were charcoal blued, and all the furniture was case hardened, usually just grey.
Actually they were more likely rust blued rather than charcoal blued and that's how Don in fact finishes his. He did state here at one time charcoal blued, but in later discussions with him he says that rust bluing is more likely based on factors such as time period (charcoal bluing just wasn't used much during the tenure of the Brothers Hawken) and color is closely matched by rust bluing.
In fact here's a quote from Don -
The few Hawkens in good enough condition to see original barrel finish are blued. The blue is fairly dark. I like the color I get by doing a satin slow rust brown, followed by boiling the barrel in water to duplicate the color. When doing the rust blue, don't overpolish or you get too bright a color. It is not the deep translucent blue seen on European guns. The rib and thimbles were also blued.
The breech and tang were case hardened as well as the lock, butt plate, trigger guard, trigger bar,entry thimble and nose cap. Not the highly colored case of modern firearms but a mottled grey case that some of the early makers called forge casing.
Also on half stocks the rib and thimbles are blued along with the barrel and that would be tough to do with charcoal blue. I've not looked at near as many originals as Don but FWIW those I have that retain some of their finish look more like rust blue than charcoal to my admittedly less educated eye.
As noted the rest of the fittings including: locks, breech plugs - patent or straight, butt plates, trigger guards, etc. are all case hardened in a gray finish - similar to what you get with Kasenit......Of course over time color case fades and can leave a similar gray finish.
For those folks interested in Hawkens who haven't perused the Buffalo Bill Historical site I recommend it highly -
here's the link to the search by maker list.
http://www.bbhc.org/collections/bbhc/filter_CFM_byMade.cfm?museum=CFM&filter=byMade - scroll down the list for the various Hawkens listed - for some strange reason they list them by first name so look for:
J & S Hawken
J. P. Gemmer
Jacob and Samuel Samuel Hawken
Samuel Hawken
W. S. Hawken
Once you get to the thumbnails of each individual rifle you can zoom in on the various images to better see the detail
One caveat - on some rifles they have photos mixed up i.e. two different rifles images and on others when you zoom in it only gives you a portion of the thumbnail shown.
You can also contact the BBHC and order prints.........
As for wood choice - to quote Don again - I could count the number of originals stocked in walnut on one hand - they were made, but are exceedingly rare.
Some additional info from Don
On most rifles, including Hawkens, the ramrods are apportioned to the bore size. Ramrods are almost always tapered but thimbles may not be. On my original fullstock Hawken which is roughly a 52 cal, all three thimbles have ID's of .485 My late halfstock is approx 50 cal. The front and middle thimble are .445 ID and the entry is .425.
As I am sure I have posted here before, Hawken barrels are mostly tapers with straights and swamps being the rarities. My fullstock is 1.040 taper to .970 and 37" (long). Fullstocks tend to be smaller barrels with less taper than the half stocks. Personally, I would not go larger than 1 1/16 at breech . With a flint tang I would go 38" long.
hope this helps..........