St. Louis Souvenir Charm or Pendant

This is a charming piece showing the Saint Louis (Missouri) Old Courthouse. It has a distinctive tall dome, which the charm shows framed against clouds. The dome was modelled after St. Peter's Basilica in Vatican City, and was completed in 1864. The pendant or charm measures .5" across and .75 long, and is framed by the famous Arch. There is some very tiny lettering on the back, but I can't make it out.