True. I don't think there's a way to tell just by looking at the bottle or it's box itself. Another way is to get a small tester from the shop first and if it turns out to be real, there are more chances than not of the non-testers being original as well.
Also, there are very slight chances of well known and big shops keeping fake perfumes. But also, the less the risk, the more the price. But i think that's a safe solution. If you are paying 3000 for a perfume, pay 500 more and buy from a well known shop instead. Or if you want to save some money, go for a proper tester instead. It will cost you half almost. You don't need the perfume box anyway.
You are welcome.