okay thanks.  So the key is that the bitcoin had to exist in a wallet, not merely exist.  I thought a BCC could be claimed so long as the bitcoin existed (was mined already), so that bitcoins that were in "limbo" in some exchange could theoretically be withdrawn into a wallet to see if the corresponding BCC had been claimed already for that pre-existing bitcoin.  It's too bad, given that BCC is $450 right now. :-(

Thanks!!