"Does a pre-Raliegh Hercules have the same sizes? My dad has one that will need an overhaul some day soon."
I think so. British Standard Cycle and Whitworth pre-dated SAE or metric standards. But, go back far enough and lots of companies had their own standards, which they didn't necessarily give up when the standards were created. Two of the unique non-standards I've run into are Raleigh bicycle and Stanley tools. Extra confusion grows from the fact that the standards deal with multiple issues such as threads per inch, thread angle, bolt thickness and bolt head size. So you can get a bolt that requires a whitworth standard wrench, but uses Raleigh's non-standard threads. But, since BSC is said to have been developed by Raleigh's competitors, I would expect whitworth wrenches to fit.
If anyone wants to send me a pre-WW2 Armstrong or Hercules to experiment on, I promise to measure carefully and report back the results.