From what I've seen, you can ferret out the year your guitars were produced from the serial #...as someone indicated previously. My GCS-6 begins with 74, the year I'd expect it was born, as it was purchased in 75. Several have asked about the value of the GCS model. Sterling indicated the higher the # of the various models, the higher the quality of the instrument at production (ie 1 at low end). Elderly music recently had a really beat 6 with an asking price of $35. I've seen others sold on ebay in the low to mid $200 range. I've also seen where folks were asking considerably more...but you can ask whatever you want. Bottom line to those wondering what their GCS-6 is worth;if you have an early model (72-78)in good shape, ask $250 and maybe come down a little from there.