Cars shipped from the factory with TTG lights in 1973 did have chrome horn grills. Black was a dealer option, but the dealer could put on chrome just as easily as black in 1973, the parts were quite obviously available. The black grills came in the retro fit kits for the LWB cars, the kit included all the parts to install the lights into the car including the switch (but no knob), wiring loom, relay, grills, lights, brackets etc.etc.

E