I don't know. My current belief is that it depends on the wavelength of the pulse. EMPs are expected to have long wavelengths, so only create big currents in long wires, so LEDs are likely to be safe, especially if not connected to anything. Small, coin-cell torches may well be safer than big 2xCR123 ones because they have less of an aerial effect.

If the EMP is specifically designed to destroy integrated circuits with a high frequency pulse, then LEDs would be affected too.