This new system had the numbers pressed into the wood.
The system was used from 1961 to 1969 and had many problems that resulted in duplicated batch numbers so the numbers from those years are approximate and exact dates are hard to come by.
It's best when trying to evalute a collectible to contact Gibson for further information that is not as easily available.
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.
The numbers 001-499 show Kalamazoo production, 500-999 show Nashville production. When acoustic production began at the plant built in Bozeman, Montana (in 1989), the series' numbers were reorganized.
MADE IN USA were also included on the transfer and some models had LIMITED EDITION also applied.
A few bolt on neck instruments had a date ink stamped on the heel area.
Unfortunately, the numbers were in no particular order. 1970 also saw the end of the orange labels on the inside of hollowbodies and acoustics.
New white and orange rectangular labels were designed for acoustics and smaller black/purple and white labels for hollow body electrics. All numbers were impressed into the wood and a six digit number assigned, though no particular order was given and some instruments had a letter prefix. From 1970-1975 the method of serializing instruments at Gibson became even more random.If the instrument has original electronics some dating can be verified by pot numbers.Once again the system was modified in 1970 to a six digit number pressed into the back of the headstock.Bozeman instruments began using 001-299 designations and, in 1990, Nashville instruments began using 300-999 designations.