Are the 9C1 center caps supposed to be steel or plastic?

I've seen these for sale as plastic with a sticker. Is there a steel one that's authentic or are these possibly the real thing? I can see cracking the plastic if you overtorque the lugs.

http://i21.ebayimg.com/02/i/000/ee/a6/0851_1.JPG

None are steel - the center caps you show are actually for truck rally wheels and not the 9C1 wheels (these center caps say "Chevrolet Motor Division" instead of the Bowtie). Of these, the real ones are made of zinc.

I don't see a problem with the plastic caps. They are fastened with the three smaller holes directly to the rim, the lugs don't touch them at all. Those look exactly like the metal center caps that I currently have. If they look the same, and they are cheap, RUN 'EM!:wink:

Well, i recently bought some caps for my car. The way they work is that you need these special lug nuts that have threads on the outside. Once you put those on, hold the center cap on, and then there are these black plastic nuts that you hand tighten and thats what holds it on. You shouldn't have to worry about over-tightening either because the lug nuts don't bolt over the plastic. And i do believe these are plastic from the factory, my dad has a chevy express van and he got some silverado rims which have chevy center caps that are plastic from the factory. Everything these days is plastic :disappoin