This answer is No. LED light-emitting device made of a single wavelength or mixed wavelength spectrum.In fact,It is actually a band of light,
we has been measured with a spectrometer.the Liquid or solid material inspired by high temperature, emit light of various wavelengths, such as incandescent light, sunlight and hot iron electrode various wavelengths are emitted continuous spectrum.This spectrum is formed by the hot solids  ,liquids or high pressure gases

Follows we think the shape means As shown in the spectrum of a LED,now ,Most of led was used blue light(centered band at 460 nm)
chip and yellow light phosphor composition a superposition of continuous spectrum:

there are several LED, for example, traffic lights, each LED particle is only one color,the composition seen one as linear, emission of light must be in here region;

The other oneis a three-color LED(it contains the RGB three colors ).we could think that it is line spectrum, but there are still several or tens of nanometers in width) mixed spectra are as follows:

The effect—–You see that the white LED is made of blue + Yellow 2 or R+G+B3 kinds of take out .