Have a round Pam clock that runs but second hand starts and stops

It has a large round mechanism on top of the actual small round motor.
Has 4 brass rods that connect the mechanism to the back of the clock.

How do you remove the round mechanism of the top of the motor? The rods appear to have a flat spot on one of the sides like you can unscrew them, it looks like the end of them protrudes out of the top of the round mechanism.

I have to ask because my replacement motor has a square mech on top of the motor.
I have pics from ebay but cant post to imageshack now