To reiterate. Guild JS I - production dates will be within 1970-1977. Some of the JS I's have a different headstock treatment - I recall a gold decal rather than the Chesterfield and inlays. The pole pieces are flipped on some JS I's compared to the neck position on a JS II. I seem to recall a satin type of factory finish offered but could not say for certain that the pictured instrument was not refinished. There were long scale (34") JS II's but I'm not sure about a LS JS I. Regardless, the proportions in the photo suggest the 30.5" scale.
The pickups are an acquired taste, IMO. "muddy" is a common and uncomplimentary comment. I would use 'fat' or 'boomy'. I think the JS I always had the deep/hard toggle (a.k.a. suck switch) and you do get two different tones with it so there is some variety. It is not the "Fender" sound, nor does it have much in common with the Bisonic family. It is its own beast.
Every so often I get the JS II out of the case and play. Ergonomically I wonder why I don't play it more and then I listen to it and after a while understand why.
My fantasy is that me or my estate would get $1000 for an original owner 1971 JS II in VG condition but I don't think that is realistic. If there are no issues and a case $500 (US) +/- seems reasonable for the pictured instrument, especially if the buyer has heard it first and could do something with the sound.