Can the manufacturer issue certificate of origin without fil

I actually produce bamboo steamers without producing bamboo sticks, chopsticks and toothpicks. However, customers always use bamboo sticks, chopsticks and toothpicks to complete the bamboo steaming and cage cover shipment. Therefore, the bamboo sticks, chopsticks and toothpicks are also inspected in our factory. However, our factory does not have the products of bamboo sticks, chopsticks and toothpicks on record. The customers say that the products without filing can not issue the certificate of origin, and the customs also says that there is no actual production Products can not be put on record. Can we produce certificate of origin for some products that have not been put on record?