Jay, what I've done is saturate the pith with super glue, let it cure then sand it flat and glue it on. With TBIII you could just add add the glue and let it sink in well then add a little more for glue up. With thinner glue like super glue if you don't pre-treat the antler will starve the glue joint.
CA is super glue. It's an abbreviation for the chemical.