Gang,
The OP's screwdriver has a "BC" series code stamped on the handle.
This code is associated with Vlchek between 1935 and 1941. Most of the Crafty tools found with this code were striking tools (i.e. chisels, punches, awls, & hammers) but a few screwdrivers have also shown up with this code.
As to the handle of the OP's screwdriver, it was originally yellow with a blue band on it. All the ones I've seen in person were yellow/blue and all had darkened with age (to be expected given the age and usage).
I hope this helps....