I've seen this on a lot of CS guitars now (ones I looked at when buying), Also I know someone with a cs-356 which is CS103xxx.Incidentally, does anyone have the original spec or any Gibson released details on the es-330L?or perhaps for the 330, but it would be nice if this could be confirmed 100% I have emailed Gibson, and although this may be completely uninteresting to most on this forum, I am very curious to confirm.Yes I realised that shortly after I had written my response.They both have a mandolin shaped neck, 9" pot, "The Gibson" silkscreened logo, Grover patent tuners, single ply binding on the resonator.
I was guessing that the '5' is either for Memphis.
And to make matters worse, the documentation of these 'out of normal format' numbers is lacking to say the least.
Unfortunately the community and customers are the last to know what's going on - sometimes by years.
Gibson USA serial numbers are pretty straightforward.
It's the Custom Shop numbering that is so very weird.
We usually set them up as 4 string mandolin banjos.