I recently picked up a very sweet 135mm Wide Field Ektar. The serial # is 0-RE208 which from what I know was made in 1954, but what is the significance of the 0 prefix. The lens has the L in a circle following the serial number and I know that that means the lens is luminized or coated. I guess this is not a really important question, but I am curious. I have searched but have not come up with an explanation for the 0 prefix. Any help on this question will be appreciated and will raise everyones knowledge level.