Yeah, got mine yesterday and caved in. Definitely legit, except for the dodgy conversion plug! Global firm ware too but I've flashed to the latest one from OnePlus site.
Got my parcel delivered yesterday. Unfortunately got home very late so haven't been able to check anything inside but it looks fine. It has Chinese packaging and the postage/delivery stickers show it as coming from France.
Im not paying the duty, will wait it out and raise a dispute I think. Unless you get yours first and confirm its all legit. If its any help, I'm here for moral support for you :)
I'm in the same boat as you. Will see what happens when the parcel comes.
I'd be terrified using this in cold showers and the rain ;)