These guys:
http://www.thehawkenshop.com/
For a low price, the Lyman is pretty damn good. Blue barrels on pre-1850 guns make me want to vomit, though. I'd strip and brown it. I have put my money where my mouth is, too. At home, I have a 25-year-old T/C Hawken with a brown barrel, and an unfired Patriot with a brown barrel. No, they didn't come that way from the factory, even back then.
A nicer, really authentic one, a lot more so than Lyman's, with a brown barrel and maple stock, is this beautiful Pedersoli for $895 at Dixie:
http://www.dixiegunworks.com/product_info.php?products_id=13404
$200 less in walnut:
http://www.dixiegunworks.com/product_info.php?products_id=13405
Bottom line: AFAIK maple was the wood of choice, not walnut. Curly maple is highly desirable. I do not believe that blueing existed; rust browning, like the Pedersoli, is authentic.
T/C Hawkens and clones (CVA, Dixie, Traditions, Cabela's, etc.) are not authentic at all. The T/C Hawken was, in fact, the first "modern muzzleloader" for hunting use, before they invented those inline abortions. I have a T/C; it shoots well. But it's not authentic, though it is a halfstock sidelock with an old-fashioned appearance. It is a great choice for hunting, if you live in a state that requires you to use a sidelock, or if you just don't want to use an inline abortion during BP season.
You can build a pretty authentic rifle from a Lyman kit, if you brown it yourself. Or you can buy a really authentic production model from Pedersoli. To go farther up the scale, the Hawken Shop is one place to contact.
Austin & Halleck is out of business. They used to make a nice Hawken, too.
http://www.austinhalleck.com/AH-Mountain.html