Hi Webb,
I have a Sigma CS-6 that I bought in 1974. S/N 9027 It has a sweet rich tone that I swear has really improved in the last 10-15 years. I tune it down a full step as it fits my singing style and seems to emphasize the excellent resonance. I love this guitar and will give it to my daughter when I'm gone. Only negative is the pearl/plastic tuning heads which I am getting replaced.   What is this guitar worth and what is the wood on the sides and back. The topis solid spruce. That I know

Thanks, Bryan