With nuclear magnetic resonance on oriented nuclei (NMR-ON) the magnetic hyperfine splitting frequency of Lu-174m (I-pi = 6-, T1/2= 142d) in Fe was measured to be 138.5(6) MHz. With the known hyperfine field B(HF)(LuFe) = -72.81(36) T the magnetic moment of Lu-174m is deduced to be 1.497(10) mu-N, which differs conspicuously from the previous literature value. It is discussed in the context of additivity violation of magnetic g-factors reported previously.