http://muonline.webzen.com/news/even...olden-colossus
They don't even have jewels as possible drops.
And to be honest once you summon one of those high lvl golden mobs they should at least drop an Errtel not to mention those limited time wings from the Golden Kundun.
They are fairly common to drop simply because you can't trade and they have an expiration time of 28 days.
Every kill I saw on the Official Server they drop at least some Errtel and some Pentagram.
On a server that is x50 you should expect a drop at least a bit better than the regular server.