The Mercury C9, D1 and D4 scoops are externally identical, but have added studs on later versions. They were used on Cougar, Cyclone and Comet models. Originals are quite pricey, but there are a few outfits that reproduce them. Do a search for scoops for the listed models to find who is making them today and prices.
Just for reference, there are two primary versions of that scoop, though they all look the same on the outside. The C9WB is the Cougar Eliminator version, the C9GB is the Cyclone version, and the D14B and D34B are the Comet versions. The first two are identical and numbered as such. The Comet scoop is an update with more stud holes to align with the Maverick/Comet hood holes, but still interchangeable with the C9 version by moving the studs to other holes. The D1 version is molded with three part numbers and the D3 carries four. You can often use this info to get one at a better price.
If your car does not have hood stud holes, you may be able to use any version, though some cars have the reinforcement cut away at the factory to allow access for if they were there. Check you hood underside. If you see no thumb-size holes, then you'll make your own to fit whatever version you buy.
Mercury Comet scoop on a Maverick hood: