Looks like a TC Black Diamond to me.  Nice, simple muzzleloader.  
Wayne, your friend should keep in mind that one can buy a brand new CVA or Traditions break-open muzzy for less than $450, or even a TC Triumph.  Not trying to degrade this thread at all... Just sayin'... if he wants to move this gun, $450 is a little steep for an outdated inline, IMO.