The U.S. Customs and Border Protection (CBP) Form 4647 is a Notice to Mark/Notice to Re-Deliver.  Pursuant to Title 19 of the Code of Federal Regulations (C.F.R.) Section 134.3:  
 
(a) Any imported article (or its container) held in CBP custody for inspection, examination, or appraisement will not be delivered until marked with its country of origin, or until estimated duties payable under 19 U.S.C. 1304(f), or adequate security for those duties (see § 134.53(a)(2)), are deposited. 
 
(b) An authorized CBP official may demand redelivery to CBP custody of any article (or its container) previously released which is found to be not marked legally with its country of origin for the purpose of requiring the article (or its container) to be properly marked. A demand for redelivery will be made, as required under § 141.113(a) of this chapter, not later than 30 days after - 

(1) The date of entry, in the case of merchandise examined in public stores and places of arrival, such as docks, wharfs, or piers; or 

(2) The date of examination, in the case of merchandise examined at the importer's premises or such other appropriate places as determined by the port director. 
 
(c) Nothing in this part shall be construed as excepting any article (or its container) from the particular requirements of marking provided for in any other provision of law.
 
It may be possible to address by marking the product container, which typically means the container in which the product reaches the ultimate consumer.  Thus, for example if the product is sold in packs of 10, marking the container for that pack may be acceptable rather than marking each individual product.   

The regulations at 19 C.F.R. Part 134 may offer up other approaches for reducing the marking burden. However, we recommend that you consult legal counsel to help determine your specific legal obligations.