In California does a finance company have the right to repo a car from a police impound when payments are not behind?

No, They would have to be behind on the car payment

The above is not always the case. It can depend on what the car was impounded for. If it was impounded for something like drugs where asset forfeiture comes into play then yes the finance company can take the car regardless of payment status. The reason for this is because there are times when the authorities will tell the finance company that if the vehicle is returned to the registered owner the finance company will lose their rights to it as well. The finance company does not have to hand their collateral back to you if it means loss of collateral, it is their car after all.