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In 1977, Gibson introduced the serialization method that is in practice today. This updated system utilizes an impressed eight digit numbering scheme that covers both serializing and dating functions. The pattern is as follows:
YDDDYPPP
YY is the production year
DDD is the day of the year
PPP is the plant designation and/or instrument rank.
Examples: 70108276 means the instrument was produced on Jan. 10, 1978, in Kalamazoo and was the 276th instrument stamped that day.
82765501 means the instrument was produced on Oct. 3, 1985, in Nashville and was the 1st instrument stamped that day.
"Quis custodiet ipsos custodes". Who watches the Watchmen ?. Juvenal, Satires VI, 347. Quoted as epigraph of the Tower Commission Report, 1987