Correct is chrome, body color and black (mostly I have seen flat black)
My preference is chrome because it makes the car look more majestic. Body color is my second choice. Chroming the shutter louvers is very, very expensive. You of course have to disassemble and reassemble the shutter assembly. that entails drilling out all of the rivets (and finding the right replacement rivits) and of course the cost of chroming all of those individual shutters. Also putting the who reassembled assembly back into the radiator shell is no fun. When I did mine on the Victoria, when I was all done, it cost about $3500! If I had it to do over again, I probably would have bead blasted and painted the shutters.
John