i have six serial number but the gibson site say this
1961-1969 Firebird, Les Paul, and SG reissues (since 1997):
YYRRRM
Y is the production year
RRR® indicates the guitar's place in production for that year.
M is the model being reissued
Reissue model codes:
1= SG Custom and Special
2= SG Standard
3= 1963 Firebird 1
4= 1964 Firebird III
5= 1965 Firebird V & VII
8= 1968 Les Paul Custom
Examples: 050102 is the 10th SG Standard reissue produced in 2005.
With this example my sg is 2003... but it is real strange