Scoops question 1973 Duster 340

No duster ever came with the dual scoop in the center of the hood...period....The twister models did come with the split style scoops but they were not the standard split style scoops....they were shorter......The only cars that came from the factory with the dual scoop in the middle as an option were 1971 and 1972 dodge demons and 1973 Dart Sports....period....J54 was the code on fender tag
You are mostly right on this one.
The J54 scoop option (also known as the dual snorkle scoop) was available from the factory starting 1972 on the Demon and was also an option '73 and '74 Dart Sports.
Some very rare Canadian built '72 340 Swingers had them as well.
Also, they were always painted flat black from the factory and never body color.
They were never offered on a Duster in those years, which is sad because I think they look great with them installed.

If the car you have has a hood scoop on it and looks to be on there since day one, I'll bet it was dealer or owner installed when the the car was new, or shortly thereafter.

On another note, the '72 Dart ones and the Dart Sport ones are slightly differently shaped where the base of the scoop meets the hood on the front.
The '72 hood is more flat there and the '73 and '74 hood has a bit of a peak to it.
Also, all of the J54 cars had 2 small (about 4'') holes in the hood under the scoop with grommets, and all of the cars I have seen with this option had a large hood Decal with pinstripes in black under the scoop.
The exception to this is the '72 Canadian Swinger which only had the scoop as far as I know.

Sooooo, with all of this being said, I would build the car the way you want with the scoop or without.

I hope this helps.
Tom.