1974 Duster Duck Wing...

Ummm? That’s how the DirectConnection spoilers were. Why would you want a solid spoiler back there? Hollow is lighter. Otherwise if it were solid it weight like 25 lbs.
I didn't know they were hollow. There really is no bottom support, just the 20 screws that bolt it down. Thought there would be some cross strip support, WHILE REMAINING HOLLOW. Who would want a 25 lbs rear wing? The trunk lid would slam closed all the time if it weighed that much....