Revolutions per minute remain revolutions per minute in the old or new currency. Minutes and revolutions are neither metric nor SAE, nor Whitworth for that matter. all of them would count turns per time period the same.

There are also 45 rpm records of several diameters, to further confuse the issue for you.

But, each one revolves on the platter forty-five (45) turns per minute (60 seconds).

Note that in common use, RCA-base records were called 78s. Even though Edison discs were, most typically, 84s. LPs (33.3) were sometimes called "33s" but mostly LPs.

I suspect that those who were victims of your discussions were not so much uncertain of the answer as unable to formulate said answer in a way you could understand.

Peter Wieck
Melrose Park, PA