This item does still drop. It does drop in Kunark era from Large Heartsting Scorpions.
It is not on them very often... probably killed 10-12 of them to get the drop.
Some say killing the scaled wolves around Kurn's gets you more scorpion spawns. Maybe... but if so a lot of them are the smaller scorpions you don't need for this drop.
What would be nice to verify is if just killing the level 11-13 mobs in the area, including from Kurn's towards Kaesora is a better way of getting the correct scorpions to spawn?
With current info, be prepared to lose some hours over this.