This brass template was used to check tolerances on bare wood lure bodies during the preliminary work on replicating lathes. This particular template is stamped “C.C.B. CO. 5100”. It was part of the quality control procedure on the #5100 series Dingbat. The knob protruding from the face of the lure body cutout wasn't part of the final product but was still attached during the early steps of production so the body could be secured to the lathe.
Several early templates were found at the Creek Chub factory & sold by a descendent of one of the families who owned CCBCO.