The valence electronic structure of rhombohedrally polymerized C-60, synthesized at 6 GPa and 725 degreesC, has been studied using x-ray emission spectroscopy. The C K alpha spectrum of the polymer was found to differ from that of the C-60 fullerite especially in the high-energy region. The observed spectra were compared to densities of states, calculated using a tight-binding approximation for three two-dimensional hexagonal C-60 networks, distinguished by the nature of intermolecular bonding. Theoretical spectra of the polymers agree well with experiment and indicate that changes in the valence band of C-60 upon polymerization are mainly due to the formation of intermolecular bonds, and only to a negligible degree due to a distortion of the C-60 cage. Rotation of C-60 within the hexagonal layer changes dramatically the electronic properties of the polymer from a semiconducting behavior for the structure with 66/66 connections to a metallic behavior for a layer containing C-60 molecules that are linked through 56/65 bonds. The occurrence of the latter configuration may explain the observed metalliclike in-plane conductivity of the rhombohedral phase of C-60.