Not sure what their correct nomenclature but each louvered vent assembly in the 1965/1966 fastback C-pillar has two painted black metal "baffles".
I have the exterior louvered part, the shiny metal mesh section, the mounting studs but no baffles (or nuts either).
If you have good pictures and dimensions of the parts, I'd appreciate it as I may have to make them myself.
DT