I use CA on antler.
A while ago, I experimented with the Pens Plus Walnut Oil finish using the detailed process that "mikepenturningz" posted that he uses on wood.
I was quite happy with the results. It gave me a shine on the antler like I wanted - more of a satin sheen than a gloss, but it still felt like antler and not a piece of plastic like CA does.
My test pen has been out there for a few months in use and the last time I talked to the girl I gave it to, it was still good as new.
I'm still not convinced I'll start doing them in that finish though. It was more of an experiment than anything else. For now, I'm still doing all of my antler pens in CA.
When I get my stabilizing kit set up, I want to try stabilizing the blanks after they're turn to see what that does. I'm going to try drilling and turning almost to final diameter before gluing the tubes in and then stabilizing. I'm hoping that will allow better penetration from both the inside and the outside. Then glue the tubes and finish turning. I'm hoping that will give me a hard finish like a plastic without looking like plastic.
I think it also depends on how old the antler is and how much of the bark coloration it has. Those that are younger and mostly solid white would probably be fine and hold up with just a polish, but those that are older with some of the dark brown or grey punky marrow parts exposed would be better with a CA finish in my opinion to seal and fill the voids.