I don't think the mantel + hood (missing) conducting smoke to a chimney within the wall thickness could have been before 1600, nor the king-post truss with bolt tie between king-post and tie-beam can have been much before 1800. I imagine there was a bit of modernisation every hundred years or so which is not recorded or fully analysable. NB dendrochronology only tells you when the tree was most probably growing; timbers have been re-used ever since timber framing was devised and estate yards could easily keep whole trunks for ages