I'm not sure I'd go quite THAT far. For instance, HOW they get that signal is pretty say from a 64 model like mine, to a last year of production 76 model. So there could be some different variables going on for sure.
There was a change in the resistance and marking points on the gage that Redfish has mentioned.
And we know they changed the fuel gage part number. The early ones have the long pickup tube and long float arm.