Not sure why the turbo/930 has the one-piece part but uwanna is correct that the parts diagram shows the 930 tail using the one-piece part.
I remember having a funny debate with my friend Mark (RIP) many years about the one piece vs. two piece. It was because his '86 Carrera (which I now own) has the one-piece and my former '87 Carrera has the two-piece. Of course one was better than two in his mind and so he poo-pooed my car for having the two separate pieces, thinking somebody had broken it in half. I said the parts diagram shows two pieces so whatever.
Whatever the reasoning, I can confirm that either of them fit the hole spacing of the Carrera tail. Note that M491 is Turbo-look and M473 is front and rear spoilers option
