That orange-dialled Autavia is pretty special and all of its very few specimens have changed hands at a considerable value - considering that it's a regular 1163 case and (apart from one) movement.
Yet with hindsight it's really a pity Heuer chose not to pursue this one at the time and it remained a prototype / limited run. It is a stunning design and I am sure it'd have had no problem selling in good numbers.
Much later, in the 80s Heuer did have a few orange-dialled divers in its line-up, I hear they are also much sought after by those who collect these. Orange could have been "the new black" so much earlier ;-)!
Cheers,
Fabrizio