Being new to the board and a collector of U.S. auxiliary markings, has anyone seen or have for sale a St. Louis Opera Glass marking? The difference between this one and the very common New York marking is that it has (St.L) at the bottom of one the double circles as opposed to N.Y. These are postage due markings on incoming mail. Values are in Centimes as in T-5, T-10, T-15, T-20, and T-25. Hope my attachment works to show an example. Gary H.
