I like hitches on the end attached to the trigger guard. (Taught line, Rolling, or slip knot) and a simple overhand on the stall end or an overhand on each side of the stall. Virtually all knots are period correct. You can consider that different knots were developed for different applications and used by different professions. Perhaps Naval knots would be more appropriate for a Navy issued short rifle, etc, and a binding knot may have been used more on a longhunters rifle, unless, of course, he had been in the Navy..... Compact knots like a slip knot or overhand are best looking, complicated hitches add interest. YMMV. No wrong answer I think.
