Looking at your Bass I see the Gears seem identical to those on my Cut-Loveri. The Bass was cut down in 1937 and a new Scroll made. The Head was purfled all around and had some French type gears at first as seen by the holes under the current plates. Then these plates were put on sometime after 1937. On my Morelli, the last pic shown, they are nearly the same except for the screw holding the cog in place.
If the gears are original to the Bass and were new when installed, it is possible to date the instrument within a certain period if you know the date of the gears.