Only fitted to very late production cars, but I don't think there is a definite changeover date - as with many things on the TR7 changes were a bit haphazard! My June 81 FHC still has the old style instruments.
The change introduced the ISO type icons to the warning lamps & the individual instruments, as well as reversing the positions of the mileage & trip readouts, and changing the adjusters to protrude through the cover. The speedo cable is also different.
Take a careful look at the ventilation sliders - have you got the ISO icon above the screen/car slider? And on the illumination strip below the dash switches? I have these on my FHC but still have the old style instruments.
So when was your red DHC built Gaz? VIN?
Tony
<font size="1">1981 TR7 FHC Cavalry Blue
1980 TR7V8 DHC Jaguar Regency Red - sadly sold!
1977 TR8 FHC EFI Factory development car Inca Yellow</font id="size1">