Re: Hi how can I identify the year of my Gibson Les Pual?
This might not help this time but I have gone here to trace lots of serial #'s,  
http://www.guitarnucleus.com/serial.html  here's what the Gibson page says Gibson Serial Numbers 
1977 to Present (Identifying the Year) 
This info is from Gibson's website 
Gibson started using it's current method of serializing it's guitars back in 1977. This was an update to the previous system which had been modified several times over the last 100 years. 
The current system utilizes an impressed eight digit number that includes a serial number and a date. Here's how the pattern works : 
YDDDYPPP
YY is the production year
DDD is the day of the year
PPP is the plant designation and/or instrument rank
Since 1989, acoustic guitars built at the Bozeman, Montana facility are ranked from 001-499. Electric Guitars built at the Gibson USA plant in Nashville are ranked from 500-999. Prior to 1984, the numbers 001-499 show Kalamazoo production, 500-999 show Nashville production. The serial numbers from the Custom, Art, and Historic division vary depending on the line. The historic reissue guitars feature historically accurate serial numbers. 
Examples: 
70108276 = the instrument was produced on Jan. 10, 1978, in Kalamazoo and was the 276th instrument stamped that day. 
82765501 = the instrument was produced on Oct. 3, 1985, in Nashville and was the 1st instrument stamped that day. 
More detailed info on serial numbers before 1977 are available from Gibson's website in Adobe Acrobat PDF format for download here. 
http://www.gibson.com/Files/downloads/bluebook/GibsonSERIALNUMBERS.pdf