The colour case hardening on replica firearms, including those made by Uberti, Chiappa, and Pedersoli, amongst others, is quite real, though it is often done by means of cyanide rather than packing in bone and charcoal. The cyanide process is entirely legitimate, and even some fine original rifles, such as Stevens single-shots, were finished in this way (though Winchester rifles were always case hardened by the bone and charcoal method). The case hardening on the new 1873s made at Miroku looks particularly good in this context.
Those who want a new 1873 with bone and charcoal case-hardening can purchase one through Navy Arms, through a partnership between Winchester and Turnbull:
http://www.navyarms.com/1873_rifles.htmlUnfortunately, the stock, although of high-grade American walnut, is of a non-original shape, and it has a shotgun butt that is both ugly and incompatible with the proper manner of shouldering a rifle of this kind. I’ve never liked chequering on beautiful wood, since it obscures the grain.
Turnbull’s case colours seem, in general, to have much more blue than original Winchesters. Mike Hunter, of Hunter Restorations, can replicate all of the original Winchester finishes perfectly, on an original or replica rifle. And indeed, one way to get a Winchester rifle with original finishes is to purchase a new one, or a replica, and send it to a restoration expert.