I have an 1861 Navy Colts Signature series I purchased in the early 2000s.Unfortunately it is missing a screw underneath the trigger guard that holds the guard to the pistol and , also is missing one of the screws used to hold an optional rifle stock to the pistol. I want to find those two screws without damaging the value of the piece. Done a lot of online research and am confused as to looking to Uberti ,Pietta or some other source of authentic 3rd Generation "Signature Series" parts. Can anyone help please?