The only thing I could find "official" was this, but it doesn't talk about labelling only 'use' of HFCS :-(
http://www.grokfood.com/regulations/184.1866.htm TITLE 21--FOOD AND DRUGS
CHAPTER I--FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN
SERVICES (CONTINUED)
PART 184--DIRECT FOOD SUBSTANCES AFFIRMED AS GENERALLY RECOGNIZED AS SAFE--Table of Contents
Subpart B--Listing of Specific Substances Affirmed as GRAS
Sec. 184.1866 High fructose corn syrup.
(a) High fructose corn syrup, a sweet, nutritive saccharide mixture
containing either approximately 42 or 55 percent fructose, is prepared
as a clear aqueous solution from high dextrose-equivalent corn starch
hydrolysate by partial enzymatic conversion of glucose (dextrose) to
fructose using an insoluble glucose isomerase enzyme preparation
described in Sec. 184.1372. The product containing more than 50 percent
fructose (dry weight) is prepared through concentration of the fructose
portion of the mixture containing less than 50 percent fructose.
(b) The ingredient shall conform to the identity and specifications
listed in the monograph entitled ``High-Fructose Corn Syrup'' in the
Food Chemicals Codex, 4th ed. (1996), pp. 191-192, which is incorporated
by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.
Copies are available from the Office of Premarket Approval, Center for
Food Safety and Applied Nutrition (HFS-200), Food and Drug
Administration, 5100 Paint Branch Pkwy., College Park, MD 20740, or may
be examined at the Center for Food Safety and Applied Nutrition's
Library, 5100 Paint Branch Pkwy., College Park, MD 20740, or at the
Office of the Federal Register, 800 North Capitol St. NW., suite 700,
Washington, DC.
(c) In accordance with Sec. 184.1(b)(1), the ingredient is used in
food with no limitation other than current good manufacturing practice.
<61 FR 43450, Aug.23, 1996>