A photo might help. If you're in Europe, that might be a Euro thing. Is your front fender chrome as well? As far as I know, all of the SR models including the D3, had painted fenders. see info & pics at the JarleF Z650 site.
In the USA I'm not aware of any KZ models with a reflector attached to the rear fender. Some models had a bracket with reflector attached to the tail light assy >> the 1982 KZ650-CSR for example. see IGNITION SWITCH/LOCKS/REFLECTORS diagram for the 81-82 650-H1/H2 CSR.
1981 KZ650-CSR. Competition, Sports & Road.