TBH the C64's colors look a lot more saturated to me in real life than on emulators. I guess it depends on the monitor or TV set you use, but even the Commodore monitor had a knob to turn up saturation, so IMO it doesn't really make all that much sense to claim that "the C64 colors were these exact colors".
The colors have been measured, and the mathematical formulas needed to calculate accurate colors are known. While there aren't a single set of "accurate" RGB mappings, there is a range of accurate RGB mappings that would cover all the hue (where appropriate) and saturation settings. Even the PAL blending is known and able to be simulated.
