Ok so let's consider a simple balance beam with all three pivot points in line.

Would you consider the pans to contribute a restoring force without the requirement of the mass of a needle?

Absolutely not. If the weights are equal there is no torque in any position.

Your question is the same as "what would happen if I picked up a perfectly balanced bicycle wheel by it's axle?" Obviously, it won't rotate because there is no reason why it should rotate.

If the fulcrums on a scale are in line, and the center of mass of the entire beam assembly (including the pointer) is conincident with point of rotation of the beam, there will be no restoring force. If the weights are equal, the balance will remain in any position it is put in. If the weights are unequal, the heavier one will tip the balance as far as it can go.

A scale must have a restoring force because a balance is actually comparing the the restoring force with the difference in the weights on the pans. The displacement of the pointer from center actually calibrates that amount on a graduated scale.