Dunno if it helps, but here's a view of coolant temp gauge with Ford description:
The magnetic gauge movement consists of three primary coils, one of which is wound at a 90 degree angle to the other two. The coils form a magnetic field which varies in direction according to the variable resistance of the sender unit which is connected between two of them. A primary magnet which is attached to a shaft and pointer rotates and aligns to this primary field resulting in pointer position. The bobbin/coil assembly is pressed into a metal housing which is attached to the instrument cluster. *These gauges require no adjustments, calibrations or maintenance. This gauge system does not use an IVR.
*This warrants comment.
Because they REQUIRE no adjustments does not mean they are NOT adjustable. Unsure of 96 vintage F-Series gauges, but it is my experience on every Ford analog temp gauge I have accessed for inaccuracy (usually reading too hot), there is a little adjustment lever just inside the back-side of gauge, accessible with cluster removed, but without gauge removal. You can tweak it with a pocket screwdriver and adjust for accuracy up or down. If memory serves, usually 1/4 to 1/3 of adjustment range nailed it.
Just a mention in case you're chasing something similar. And too, I've never tried it on Fuel gauge or Volt meter.