I have both - the so call pre-production which is 100% IDENTICAL to the production unit that I received 2 days ago from DJI.
This pre-production talk is just a myth - the box, contents, even down to the little drawstring bag with propellers are the same. Who puts stickers, manuals etc into a pre-production unit?
Would be good to see your new p3 flying as far as your pre production p3. I am sure Heliguy had a flight of around 5k.