I have been looking at RB Sungalsses. Does anyone know how to really determine if whether the one i am getting is not fake. Every shop claims to be providing the original one but the price can range from 350-680 for the same specs. Looking at RB3293 polarized.

Is there a way just by looking at certain markings on the specs that i can determine it's genuinity
Eg: i was told tat on the left lens there will be an imprint of RB on the lens, however 1 salesperson said that if the lens is plastic thus the imprint would be visible from behind and if glass oni visible from front, contradicting from another salesperson who said there is not such way to distinguish them.

Confused and afraid that i get the wrong one.

Advices to spot with pics wud be highly appreciated = )