Comparing wiring diagrams, it looks like the difference is for the light bulbs. Post #21 in this thread has a wiring diagram that should match the chrome switches (8 pins, no lights) http://www.peachparts.com/shopforum/showthread.php?t=300430&highlight=sausage&page=2

The other wiring diagrams have an additional wire for the lights. This will only be hot when the headlights are not in OFF. It may be one each hot wire, for a total of ten for the black switches, or it may be an additional ground. The diagram doesn't show a tenth pin. I would think it's an additional hot wire for the bulb based on the drawing of the switch, but can't say for sure. The two pins may also be one hot and one ground.

The upper groups top center and the lower groups upper left (in the photo) appear to the be the "extra" pins. The metal strip from the top center to the corresponding position makes it appear that performs the same function.

The two triangle groupings are then similar between the chrome and the plastic.