That sounds like a fuel gauge spec. I've got a 77 and a 93 FSM but haven't found a spec for the temp gauge in them.
As I stated, they are the same FOR ALL GAUGES, fuel included, excepting the ammeter. The specific tester Mopar used back in the day tested all the gauges with the same values.
The tester is Mopar C-3826 here's a pdf on it's function
