That is a sweet gun,
do not let anyone near it with hot blue,rust blue is the only way to go.Jeff posts on the doublegun board (happy to provide a link if that allowed on here)from time to time and may be able to help with info.Another gun guy who is into those Sauers is Kirby at vintage doubles.I think I he knows Jeff S too.

http://www.vintagedoubles.com/index.php