NNP

Serial Numbering.  Consecutive numbering of medallic items in a limited issue to indicate that a quantity, not greater than that announced, has been issued. When all consecutive numbers in a series are not used (as 1–60, 65–70, 100-110 for example), this is known as interrupted numbering. Occasionally the year of issue, a trademark, other lettering or symbols appear with the serial number. If the piece is reeded and space is desired for numbering, the reeding may be eliminated in an area for the edge marking; such an area is called interrupted reeding. Serial numbers should be included with other edge lettering; as a number alone leads to confusion. For machine numbering the zeros are used ahead of the number; and 006 is confused with 900 as there is no orientation without other lettering. Numbering can be applied to the edge of a medallic item by hand (hand numbered), or by machine (numbering head).  See edge lettering and numbering.

excerpted with permission from

An Encyclopedia of Coin and Medal Technology

For Artists, Makers, Collectors and Curators

COMPILED AND WRITTEN BY D. WAYNE JOHNSON

Roger W. Burdette, Editor