These gloves are needed for an addon. In order to sell these to Elane you need to have that addon first or you have to be a free account player. Due to only being dropped by hunters they can be somewhat rare to see.
When the sniper gloves were implemented on the Summer Update 2006, they could be sold over and over again to Elane because the NPC did not take and delete them after handing out the money. This bug has been fixed since then.