Yes, it is difficult to tell authentic aviator sunglasses sometimes. Here a little advices. First, you shall look at the box of your ray ban sunglasses, If there is a a recycling logo, and a semi-permanent sticker that wrote manufacturer and distributor details, lens and frame type of the sunglasses, the sunglasses are probably authentic. Besides, you can check if there is engraved Ray-Ban logo on the sunglasses frames. If there are ray ban logo on the frames, the sunglasses are authentic.
Several general tips for you to judge the ray ban aviator sunglasses' truth. First of all, you should see the logo which is usually printed at the right side of the right lense. Then, you see the welding places of metals. If it is not smooth and delicate, it will of course the fake one. Next, you see the printed words in the mirror bracket which should be flowing. Last, you could see whether it is in balanced when put in the table which can best tell the manual work.