The low-temperature specific heats of an initially amorphous Pd-Si alloy subjected to various heat treatments are measured in the temperature range 1.5-4.2K. All the results fit well to the usual equation C= gamma T+ alpha T³+ delta T⁵. As recovery, or crystallisation, proceeds with heat treatment, the Debye temperature theta _D is found to increase, while the delta coefficient decreases. It is found that the lattice specific heat behaviour can be interpreted on the basis of a comparison to the observed relationship between theta _D and delta in a number of crystalline metals and alloys. This comparison suggests that the lattice vibrational modes of an amorphous and of a crystalline Pd-Si alloy at low temperatures are rather similar to those of many crystalline metals and alloys, and that the observed change in the theta _D and delta coefficients due to the heat treatment merely results from an increase in the packing fraction of the constituent atoms.