Optical injection locking of semiconductor lasers has attracted significant attention due to its applications in laser analysis, modulation characteristic enhancement, and nonlinear dynamics. In many cases, the analysis of the optically injected laser is done by simulation, requiring an accurate laser model and, therefore, an adequate modeling of the gain compression at high photon densities. We use the Kobayashi-Lang rate equations to numerically compare the stable locking range considering four different gain models. Results reveal that at low bias currents, gain compression is significant only under weak injection regime. In contrast, for higher bias current, gain compression must be considered both in weak and strong injection regimes.