Pretty damned close.
It is a CIE chromaticity diagram. Perception of luminous intensity does come into play. I got the data from
http://cvrl.ucl.ac.uk/ and plotted it, teaching myself to use gnuplot along the way this morning. The colors are only approximate, as no device can render every perceivable color as the diagram would seem to imply.
Single-wavelength sources like LEDs would lie close to the horseshoe-shaped edge, and white light would lie somewhere near the (1/3, 1/3) point marked with a black dot.
When you see a white LED datasheet, you get a chromaticity coordinate like (x=0.31 y=0.32) instead of a wavelength like 470nm you get with a blue LED. This gives you some sense of how white the white is.
Author