The law does not specifically require that the country of origin statement be placed on the principal display panel, but requires that it be conspicuous. If a domestic firm's name and address is declared as the firm responsible for distributing the product, then the country of origin statement must appear in close proximity to the name and address and be at least comparable in size of lettering. (U.S. Department of Treasury regulation)
And this from the USDA:
On May 13, 2002, President Bush signed into law the Farm Security and Rural Investment Act of 2002, more commonly known as the 2002 Farm Bill. One of its many initiatives requires country of origin labeling for beef, lamb, pork, fish, perishable agricultural commodities and peanuts. On January 27, 2004, President Bush signed Public Law 108-199 which delays the implementation of mandatory COOL for all covered commodities except wild and farm-raised fish and shellfish until September 30, 2006. On November 10, 2005, President Bush signed Public Law 109-97, which delays the implementation for all covered commodities except wild and farm-raised and shellfish until September 30, 2008. As described in the legislation, program implementation is the responsibility of USDA's Agricultural Marketing Service.
If that quote refers to the "Country of Origin" (COOL) provision of the Farm Security and Rural Investment Act of 2002, chocolate isn't covered. The only foods covered now (due to two delays)are unprocessed fish and shellfish. In 2008 (if it's not delayed again), the labeling will be mandatory on "muscle cuts of beef, lamb, and pork; ground beef, ground lamb, and ground pork; perishable agricultural items and peanuts."
If any of the above foods are processed (such as canned tuna fish, creamed frozen veggies, breaded fish) they needn't be labeled, and neither do foods served in restaurants.