I would build whatever appeals to you, being in Utah, everything here is fur trade era, yet I built one of Chambers Isaac Haines rifles and absolutely love it. No one at any of the rendezvous I've been too has ever said anything about it not being the right time period. Even shot a nice Muley with it this fall. I have a Chambers York kit also, still in the box, just haven't found the time to work on it yet.