i have what appears to be a guild m75 1976 model (according to the serial # 137374) it is a black solid body with what appears to be humbucker pickups--it has 2 volume controls--2 tone controls--a smaller knob which is numbered 1 to 9---with a 2 way switch above it--and a 3 way switch like a les paul. can anyone tell me about the 2 way switch and small knob as to what they do. i have played it and the switch seems to be a coil splitter------- also the general value of this guitar---- it has some scratches on back and a nick or two here and there--it was played professionally for many years but still plays well any help would be greatly appreciated