I remember when Bytecoin was released; the claims to have been used for years were clearly wrong, but I couldn't figure out what the real story was skimming the forum posts. I'm glad someone figured it out!
Someone should see if they can dig up transaction volume data to estimate how much the Bytecoin people made. :)
It is very easy to tell if a coin has been premined by checking the state of the block chain for the number of outstanding coins. The coins with large premines are usually outed withing an hour of their release.