First off, on the Rib measurements, were they inside the Top and Back or including them?
On the wood of your Back and Ribs, again it looks like Slab or rolled cut Maple like you find in Veneer or Plywood. Maybe even Birch but the closeups are blurry and I can't see the grain clearly. Please, look with a flashlight and magnifier glass along the edges of the Bass and Rib-to-Rib joints and tell me if you see any hint of laminations there. I just can't see it well enough in these pictures.
On the origin, looking at the angle break side view with the outer rib linings it looks Germanic/Bohemian but even more so now than before. The Varnish also looks fairly new so I would guess it was re-finished not long ago.
The wood on the Back and Ribs are very unusual for a Bass from this region. The purfled design in the lower Back is similar (but not identical) to Basses
made by Pfretzschner or rather Markneukirchen shop Basses.