I think that picture you posted was misleading? It kinda looks like that but not really black like that. Not sure, the color is kinda weird. I never heard of black a-spec wheels though. Even that link I sent you, they don't look like that. Like, at some angles they are black/gun metal.
Yes, they've been on Ebay/Curry Acura for that price for several months at least. The 17" gunmetal are the ones you're looking for if you want to run the ones intended for the RSX. The 18" ones are quite a bit more common, though, and I've seen them going for 700-800$ used on eBay.