How do you know if Ray Ban's are real?

I found an old pair of Ray Ban sunglasses,but I don't know if they are real. They have �B&L RAY BAN Frame France written on one arm and on they other they say Folding WAYFARER�. they have the Ray Ban written on the sides. But they don't have it on the lens. It has a light BL on the lens. I just always wanted to know if they were real.