Is the whole under side painted the same as the exterior or is there anyarea that shows primer?
The idea was to cover all the surface (top and bottom) with exterior color. OF your getting detailed there would be a small (maybe 1/4-1/8 inch) strip that was the shadow from the hooks that held the hood to the rack
No effort was made to get inside the hood but any lack of paint would have been a mistake and might have triggered a repaint by an inspector. Runs are a different matter on the bottom side