They have 1-2 more agi than the Blackened Defias Leggings, 8/9 agi/stam scaled to 19<(9/9 unscaled, 10/9 scaled to 19?), dark leather pants are just 12 agi.
I think they can be found in WC and BFD chests, scaled version drops in those dungeons and from kalimdor rares/random world mobs of the same level range (16-24).
They’re not grandfathered but kind of rare/hard to farm, I want a pair for my 19 rogues balanced agi/stam gear set.
Not sure about the price, they’re worth around 5-10k just for transmog so maybe double/triple that?