For internal use within an agency, alphabetic codes excluding letters “I” and “O” may be prefixed or suffixed to the national stock number as CM7520-00-123-4567 or 7520-00-123-4567CM, as required for supply management operations. Numeric codes shall not be affixed immediately adjacent to or as a part of the national stock number, nor shall codes be intermingled in the national stock number.

[41 FR 11309, Mar. 18, 1976]