The original robot's brain cup had oval light rod holes exactly like the Levenick brain cup, as is evident from the following photograph.

How do we know that the brain cup is secured to the brain by only four screws? Perceptive fellow B9 builder Marc Chabot took a quick glance at the following photograph of the original robot's brain and instantly noticed the four screw holes around the central hole in the bottom plate of the brain.

(photograph courtesy of the B9 Robot Builders Club website)

Note the presence of the large, off-center hole. To my knowledge, none of the reproduction B9 brains have such a hole because only a small hole is necessary to accept the drive shaft from the motor that turns the crown and light rod cam. Perhaps the hole in the original robot's brain was much larger than it needed to be. On the other hand, perhaps it was exactly the right size in order to accommodate the mechanisms that animated it. I believe that I speak the truth when I say that no one seems to know how the original robot's brain motors operated to spin the crown and animate the light rods.

The ingenious design that B9 robot builders use to operate the spinning crown and light rods was the brainchild of Scott Sanderson.

(image courtesy of the B9 Club website)

This design and an accompanying essay can be found at: construction/detail analysis/Light Rod Analysis by Craig Reinbrecht, at the B9 Club website.