No, they did not come that way from Ford. The chrome and argent grilles had gray (argent) inserts. The only grille that had black (dark charcoal) inserts was the black (dark charcoal) painted grille, which was all one color.
What color is your radiator core support?
Most radiator core supports were painted black, but I have seen some that were painted gray and others were painted the same color as the body. If it isn't black - and you paint your grille inserts black - the radiator support color will show from the front of your truck. Also, most radiators are aluminum colored, so that will show as well.
Gray inserts will "hide" the components that are behind the grille better than black. If you paint the inserts black, you would also need to paint everything behind it black as well for it to look right.
Lucille: 1985 Ford F150 XLT Lariat
*Colors: Dark Canyon Red exterior, Canyon Red interior
*Engine: 5.0, CompCams 31-230-3, "Thumper" E7 heads, Edelbrock Performer intake, Autolite 4100 carburetor, DuraSpark II ignition, Thorley Tri-Y headers, Flowmaster dual exhaust, H-pipe.
*Drivetrain: AOD transmission, 3.55 gears, 2wd.