wheel caps

I have a 79 zx black with red interior and in the back storage compartment was a new wheel cap and it is chrome like the ones on the car but the background color behind the z is gold metallic.. but of course there is only one.. It looks really nice and I would like to find three more and change out the ones that are currently on the car.. any body ever see these. I have looked several places and cannot find anything of the sort...