Did Guild use wide frets in certain acoustic applications?
My 1976 F50R came new with low, wide frets. It was common for the day. I knew three other performers at the time who all played 70s Guild acoustics, and their guitars had the same low, wide frets.
If so, could that complicate a routine nut/saddle change.
Nuts have one measurement of concern: nut slot height. Nuts are slotted so that the strings stay in place, separate from one another. The depth of the slot contributes to the ease of playability. The bottom of any given nut slot must *not* be below the height of the first fret, or string buzz will occur. To the degree the slot is higher than the height of that first fret, greater force will be required to depress the string against the first fret, and playability will suffer. *If* a nut was custom made for low frets and a subsequent fret job installed a taller fret wire, the nut would need to be modified (slots are filled with bone dust or the equivalent and re-cut to the proper height) or replaced.
To assign string buzz to a fret as the cause, if the fretboard is flat, a straightedge can be laid across the frets to "hunt" for offending frets (frets that are too tall). If there is forward bow in the neck and you have the ability to tighten a truss rod to compensate and flatten the fretboard, the straightedge test can still be applied. Frets can then be leveled, where they are filed/sanded to be the same height up and down the fretboard (this step necessitates re-crowning and polishing each fret). If your neck has a back bow (which will typically result in string buzz) and either loosening a single action truss rod or adjusting a dual-action truss rod fails to overcome and reverse the bow, the guitar should go to a qualified luthier.
Saddle height is definitely relative to fret height. Assuming that the frets have been leveled, the nut slots are properly cut, and string buzz still occurs, a shim can be placed beneath the saddle (in the saddle slot) to determine if the buzz being heard is fret generated. The objective of this simple test is to get the saddle tall enough so that the strings easily clear the frets. If you no longer hear string buzz then you have identified the culprit and can shim the saddle to the appropriate height.
If you were wanting to keep a nut and saddle that had been customized for very low frets, and all other potential sources of your "consistent buzz (overtone)" were ruled out (irregular fret height(s), a loose or snapped truss rod, a wonky brace or glue joint, or even an odd quality of the bone used for the nut or saddle resulted in some crazy harmonic), and a new fret job was definitely in your future, and there wouldn't be enough material left at the top of the nut to fill and re-cut the slots - then replace the frets with wire of your choice, narrow or wide, and either file the new fret wire down to accommodate the nut (perhaps a bit wasteful) or simply shim the nut.
