I recently acquired a '78 Guild S300-D and brought it in to a local tech for a set-up. When I picked up the guitar, the tech told me the nut was unglued, and that a sliver of a pick was placed underneath, acting as a shim. He removed the shim and properly glued the nut back in before re-stringing. Now the guitar is intonated perfectly, but the action is WAY too low. (Now I know why the previous owner put in that shim.) I attempted to adjust the bridge to compensate, but that only raised the string height from about the 12th fret up... no effect at all on the lower frets. Do I need a new (taller) nut? Will that throw off the intonation?