You are correct about Savage floating bolt heads not needing lapped because they float. The floating head makes sure the lugs have even contact but it also has a downside. One of the things that makes a rifle more accurate is to square the bolt face to the boar. That's what you do to a solid bolt but with the floating head the relation of the bolt face to the boar is determined by what the lugs lock into in the action so lapping lugs a waste of time. At least that's how I understand things.