How bad is the old finish. I would say there are 2 options 1) remove the entire old finish (220 sandpaper) and re-appply (this option you may lose the name on the side or 2) take 400 grit paper and rough up the top coat of old finish not going through (here you can save the name on the side).
As for finish options (available locally) I would go with Tru Oil (gunstock finish). It is about $5 for a bottle available at most sporting goods stores...and sometimes wal-mart...put a coat on with a cloth, let dry, then buff it with 0000 steel wool, then again.
If you choose to sand all the way down to the wood it may take 10-20 light coats. Best of luck.