I've got some nice chunks of reclaimed heart pine here that I've made pens out of, and you would do well to have it professionally stabilized (I recommend River Ridge if you decide to go that way -
http://rrpwhite.com/stabilizing page.htm). If there's heaving graining, you have to be careful when you're sanding, because the soft stuff will sand much easier than the hard stuff, much like working with cedar, and you'll end up with a textured feel to the pen, which isn't always bad!.
If you have it professionally stabilized, you'll be able to get a durable glossy finish on it, but if you use it as is, consider doing a wax or oil-based finish and market the pens as 'natural wood that will build a wonderful patina over time, with use'. Even if you put a thick CA (which isn't very flexible) finish on it, it'll look great until they put a fingernail or sharp table corner mark in it, which will degrade the base under the CA, causing it to flake, chip and otherwise erode.
If you use a CA/BLO finish, you've got a bit more 'rubberyness', but it's still going to be easy to mar it.
I'm actually making a skew handle out of the stuff that I have, but I'm planning for it to take some bumps and nicks. By the time I die and leave it to someone special, it'll have lots of blood, sweat and tears worn into it, which makes it cool, too.
Remember in the movie 'Crossroads' where the old blues guy accuses Ralph Maccio of buying that old guitar because he though it looked 'authentic' with all of its wear marks? Yeah...like that.
