Van, Sorry I missed your question re: screw in back end of the trigger guard. This was not his usual method of fastening the guard to the stock. The trigger guard, however, is another signature characteristic of the Bonewitz/Womelsdorf school. Look closely and you will see three 1/2 octogon raised platforms on the guard. This raised platform is usually found on the rear ramrod extension as well. I do not know if the screw is original to the gun or not.
There are a number of other Bonewitz/Womelsdorf signature characteristic that appear on the gun. When this gun hits the museum they most likely will be covered. If not, feel free to contact me with your questions. Regards, HIB