Photometric metallicity ([Fe/H]_phot; top), spectroscopic calcium-triplet-based metallicity ([Fe/H]_CaT; middle), and the summed equivalent width of the Na I λ8190 doublet (EW_Na; bottom) vs. heliocentric velocity for stars in the NE shelf fields (Table 1) classified as M31 RGB stars (red circles) and MW stars (gray crosses; Section 3.1). Stars in the NE3 velocity peak (Figure 3) are outlined in black. We show [Fe/H]_CaT (EW_Na) measurements with uncertainties δ[Fe/H]_CaT < 0.8 (δEW_Na < 2 Å), where the large uncertainties are due to the low spectral S/N. Neither [Fe/H]_phot nor [Fe/H]_CaT is physically meaningful for MW stars, but they are useful as population diagnostics.