That first picture is Bubinga and birch bark with a moose antler winding check. My finish on all of those types of handles is Tru-oil. Depending on how many coats and how you rub it out you can get anywhere from a high gloss to satin finish. I also core out all my wood grips to reduce weight.
here is a whitetail burr,burl cork and bubinga grip finished in tru-oil
here is another antler zebrawood combo finished with tru-oil