Here are a couple of tools with groovers. These are not old, but made like old ones. the top photo is a piece of rib bone. It has sizing holes cut into it also. The "hook" shaped cutout is the groover. You just place the arrow shaft into the cut out, and as you pull the shaft through, the pointed end of the hook cuts the groove.
I did not make the one in the bottom photo. It was made by a buddy of mine, Ken Weidner. It is made from an old table knife. It has two groovers cut into it, a smaller one on the left and a larger one in the center of the blade. The right hand side of the blade is made into an arrow saw. Both types of arrow tools were common to plains tribes in the 1800's. Curtis