from what we can tell, it appears all drones come from the factory. i think the question is "when." if you are waiting for a future batch, i think you'll be fine. if you pull your "new" drone out the box and you fire it up and as you are preparing to update the software and you look to see that the software version already in the drone is 0.0.2.1 or something else that looks like beta software, then you might be concerned about old stock.
personally i would never buy a drone from any chinese merchant selling drones on amazon. for me, buying a drone is more than just the price, after support, warranty, etc. i'm concerned about safety and if that particular drone has been tested, has the proper fcc (markings), what kind of battery it has, etc. this is usually only of concern when that merchant has very early pre-release inventory and is selling the drone at a price other than msrp.