RE: Insulator help
As usual, Bill has it all correct. The pony was made by Ohio Brass, a B inside an O, the O being difficult to see. Both are very common, about worthless to all except the most recent "Mud" (Porcelain) collector.
Jim Sinsley will buy or trade for WAW-WAW, Owls, "Littles", Oddities, Santa Ana, CA. or Coeur d' Alene, ID. bottles.