I am actually a project manager for a commercial conctractor that happens to have a BA in architecture and an MS is construction management.
With that said, I have no idea when it was standardized. A good bet though would be to measure things like floor to ceiling height as you mentioned. You could find a house built after the "cutoff" that's still got whacked dimensions. Especially if you go back a bit and things have settled and shifted.
If this is really a concern for you, you're opening a whole can of worms. Window can be another nightmare. Houses built as recently as the '70s can have windows that are not sized to today's standards. Which makes buying blinds and other window coverings, as well as replacement window, a custom prospect (meaning more expensive).