[aerohead]

I'm also not seeing dimples,but do see the 'bubble-top' as freebeard has shared already.
Abarth I think was the first to use it.Frontal area is trimmed a little.The corrugations in the sheet metal add stiffness,allowing thinner material and weight savings.
If your existing roof was designed like this,it would be good to carry that feature into the cap.At least for some distance necessary to blend it away.But I don't see any benefit just doing it with the cap if the cab roof is conventional.
As to the outside edges,I don't know.They may be hiding hinges under there.Don't know.