I’ve got a bike described as ‘pure process blue’ so obviously this does happen. Bike had been powder coated so it was probably actually RAL something or other.
CMYK is at least additive, RGB is a subtractive model completely unsuited to describing colours not on monitors.
I imagine comparing a CMYK chip under a diffuse true daylight source with chips painted in the available colours would be the most accurate match, although you could use a conversion service to get from CMYK to whatever system the paint is produced in but you’re going to get inaccuracies at every stage. Beware drydown. Wet paint and dry paint are never the same colour, and gloss vs matte has quite an impact too, as do dissimilar viewing lights and different people. Be aware paint changes colour with age often, so actual frame may be better if less convenient than CMYK chips.
Actual outdoor daylight as suggest by Tillydog would obviously be fine also.