Section 20.179 - Package identification number or serial number(a)Requirement. A dealer who fills packages with specially denatured spirits shall mark each package with a package identification number, in accordance with paragraph (b) of this section, or a serial number, in accordance with paragraph (c) of this section.(b)Package identification number. A package identification number shall apply to all of the packages filled at the same time on which all of the marks required by § 20.178(a)(1) and (a)(3) through (a)(8) are identical. All of the packages in one lot shall be the same type, have the same rated capacity, and be uniformly filled with the same quantity. A package identification number shall be derived from the date on which the package is filled, and shall consist of the following elements, in the order shown-(1) The last two digits of the calendar year;(2) An alphabetical designation from "A" through "L," representing January through December, in that order;(3) The digits corresponding to the day of the month; and(4) A letter suffix when more than one identical lot is filled into packages during the same day. For successive lots after the first lot, a letter suffix shall be added in alphabetical order, with "A" representing the second lot of the day, "B" representing the third lot of the day, etc. (e.g., the first three lots filled into packages on November 19, 1983, would be identified as "83K19," "83K19A," and "83K19B").(c)Serial number. A consecutive serial number shall be marked on each package, beginning with the number "1" and continuing in regular sequence. The dealer shall use a separate but similar number series for packages containing specially denatured rum. When any numbering series reaches "1,000,000", the dealer may recommence the series by providing an alphabetical prefix or suffix for each number in the new series.(d)Continuation of numbering series. If a change in proprietorship, name, or trade name occurs, the numbering system in use at the time of the change may be continued. If serial numbers are used at the time of a change, the numbering series in use at the time of the change may be continued.Sec. 201, Pub. L. 85-859, 72 Stat. 1360, as amended ( 26 U.S.C. 5206 )