We present correct assignments to the Raman spectrum of an epitaxial hexagonal GaN film grown on (0001) sapphire, published by Zhang et al. [J. Vac. Sci. Technol. A 14, 840 (1996)]. These assignments are supported by our additional polarization and incident angle-varied Raman measurements. A method to distinguish the Raman features of the epitaxial GaN thin layer from those of the sapphire substrate is presented.