I'd say either Starr or German, leaning towards German. It dosen't quite look like a Starr but is definitely a close cousin, maybe a militia or private purchase piece? Or just an early pattern Starr? It probably saw use around the War of 1812 or maybe the 1820s. In terms of restoration, I'd simply conserve the metal, it gives an interesting insight into the way the sword is put together. The grips are missing, but the tang is intact which is unusual. You can see very clearly how the tang runs through the backstrap and then is peened to hold the assembly together. You ought to take some more pictures and measurements, prehaps someone might find it useful to produce replicas an learn the old manufacturing techniques.