The key to the acrylic is to start at the base with burnt umber and once you get on there, try to get it off (serious), and then with the paint damp towel you do some sponging, then move up the antler with some raw sienna with the same trick, ad a dash of yellow ocher (just a dash), do the raw sienna all the way up the antler and then work hard to get it off the tips and not so hard to get it off as you go down. A touch of ivory on the tips rubbed down adds some highlights. Then let it dry and then scrap some of the paint of the nubs at the base. Then spray down with matte clear finish.
Hmmmm...sounds more complicated when I type it out. You can also do this with already stained antlers to give some more depth.