A simple, semiempirical model that includes many-body polarization is used to study the ground and excited state properties of Ar-N(+) clusters (N=3-23) at 80 K. For purposes of comparison, a model that does not include many-body polarization is used to study clusters with N=3-27. Monte Carlo simulations are used to calculate the average properties of these clusters. The model is similar to one previously used to study argon cation clusters without many-body polarization. The photoabsorption spectrum is in good agreement with experiment; in particular, the photoabsorption spectra for cluster sizes 4-10 do not show the blueshift that is seen with models that do not include many-body polarization.