This Brock porkpie is from the late 1950s. The size tag is very similar to what was going into Stetsons and Mallorys of the period. I wonder if this was made under license or if it was just a coincidence.
John McHale didn’t just make enormous brown captoes, they also made something a bit sleeker as this pair shows. These are a bit later- note: McHale vs. John McHale, and probably date from the late ’50s/early ’60s. The Mad Men era.