All of the regular production stainless Contender frames had the etched cougar head on them, and all are late easy open vintage. You don't see many stainless "C" frames because in comparison to blue, relatively few were made.
While stainless frames bring a little more than blued frames, that trend doesn't seem to follow with the used stainless barrels. The black grips depend on what they are for what they add to the value. Pachy grips/forends bring more than the composite sets do.
Price is all about condition AND the supply and demand where it is being sold. At a local show, gun or pawn shop, by an individual locally or if being sold on-line via a board classifieds or auction site. Prices can vary a lot IOW depending on where sold and in what part of the country. At shows, in shops and on reserve auctions folks tend to be real proud of them though.
It's interesting your question comes up right now. I just got an email from a friend last night who had a table at a local gunshow this past weekend and sent me an update on it. A stainless 223 Contender pistol was sold by a gent with a table next to his. The show was in WA state, an area that has always been well known for lower than average prices on firearms. I don't know what barrel length, grips it wore or its condition, but the gent sold the pistol early in the show for $650 (and an early framed blued 45/410 for $450). I would call that higher than average buy quite a margin, especially for in that state.
Average for a stainless 223 should probably be more like $450-500 depending on condition and which grips IMO.
L.