I have a Sigma DM-43 (I think it is a 43 or 4S??? - hard to read) It was my dad's; unfortunately he died right after he got it so it is never played. Can anyone let me know @ this model & price it would go for. It is mahagony, says Sigma Guitars Est. 1970 @ top & it was purchased @ 1997 or 1998. Thanks so much!!! Kat