Well, I've got seven of them, apparently all from trading, and as far as I can tell, several of them are of legitimate background. I've only actually caught one legendary so far, myself, but I accidentally lost him on the GTS for a Dialga. Fun stuff. Anyways, I'm probably logging off for the day, so take your time considering it, you've got all today and some of tomorrow before I'll even be back online.
If any one else is interested, keep in mind I have a few Manaphy, extra Mesprit, Uxie, and Azelf, and also a spare Cresselia, too.