[DonVoigt]

Brien,
Be careful before you start changing things, pretty soon you will have way too much money in this pistol, JMO.

Cheapest/best way to "restore" it is to replace the rear toggle with a "std." one, maybe $30-50.

A navy toggle could cost you $600 to $1000, unless you get really lucky. A repro Navy rear toggle piece with sight is about $400! Then the taller rear sight will not shoot to vertical point of aim with the original front sight.

A .30 matching luger did not start out with a 1939 date, must be something else or else it is likely a parts gun, re- numbered to match. But more better pictures of all markings(close up) would help.