#1 - Sept. 16, 2015, 4:27 a.m.
When you ID legendaries, it will show you right away which ones are ancient by putting the said ancient items in curly braces. Like so:
http://i.imgur.com/eBpxWS6.jpg
Notice in the list of items, a few of them are listed within braces: { } Those are the ancient items.
BTW, all those legs are from a single T10 rift, which is certainly a personal record for me. Of course, they were all salvage.