While numerous examples were likely made before the Gould Act, it is not cost-effective to needlesly engrave multiple plates or moulds for a utilitarian bottle meant for a catalog that any bottler with a tight budget might select from. Many bottles before 1910 were full ABM just as many bottles into and after WW1 in America were, like this, made by being BIM.
Interesting. I'd have said that a BIM bottle after WWI was a very rare critter, as WWI, as all wars do, pushed productivity and technology forward. Do you know of a confirmed post WWI BIM bottle that can be confirmed was blown after WWI as opposed to a reused bottle or one from old stock?
Say a BIM med or booze bottle with a label for someone not in business before 1914? That would be 100% proof it was blown after the start of WWI but it would be fairly good circumstantial evidence it was.