The legendary ground mount is not upgraded to a flying mount. I have the mount and nothing is changed. GM has also told me it's not a bug, and it will remain a ground mount. So yes, most likely it was a fake screenshot. No reason dev team would update an item pre-bc lvl 60 that only .000001 of the WoW population has. Anyways, just thought i'd clear that up.
Here are some pics incase you want to see it for your own eyes
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Scarab Lord Reiatsu -70 -Troll Rogue
Horde Runetotem - <tys> guild