I don't think the hood blister from the 91/92 Z will work on a std hood - the Z hoods had indentions in the hood shaped like the blister, where a std hood has no indentions.
Don't know about Classics nose cones, I got my new one from Hawks (a sponsor here), and it was a new GM part, so it was perfect - but I haven't seen any for sale from them recently, maybe I got the last one they had. But I'd call them to see if they have or can get any more - mine was $400 from them.
www.hawksthirdgenparts.com They may also have a good used one around.
The chin spoiler is also a rare find, since 91 &92 cars had the aero ground effects - last time I saw a new one it was over $400. Check with Hawks for that as well - they may have a good used one available.