The first time I looked at the picture I did not see the word "chicago" under the lion. I am now certain this sign is from the same company out of Chicago that was seperate from Lion oil of Arkansas that I collect. The Chicago co. I don't believe ever marketed gas but only lubricants. (If anyone knows different let me know). I know an old salesman from Lion oil (Ar), and have asked him about Lion Oil (chicago) and he told me they were two seperate companies in the day not affiliated.
I believe Ron's sign to be the first like it found that I am aware of and very, very rare and desirable (even with a few chips). Always remember, just my opinion as I am NOT an expert. Congradulations on finding the sign. Now the question, how much?