Talking with suppliers is always a good idea, but if you are trying to buy brand names you run the risk of simply being told what you want to hear, regardless of what the actual truth is.
With documantation, I've seen replica documentation that the brand owner wouldn't pick as fake. Seriously, if they can make a tennis racket that looks legit, they can replicate paper work without too many problems.
As Richelle has said, If you want brand name tennis gear, forget about China......and that's the best advice anyone will be able to give you, full stop!