OK - I'm confused.  I've got a '63 split Window that I'm going to re-paint
because it's got blisters showing up. The confusion is because I don't know
if Gel Coating is a must or not. I have 2 restore shops that tell me it is
and the paint won't last 3 years if I don't and 2 ...

I have a 1996 LT4.  The analog oil pressure guage drops to zero and
the "check guages" light comes on when the car is idling.  The needle
moves when the car is under acceleration and the light goes away.
I've owned the car since 1999 and this is a recent "feature".