Guided wave based nondestructive evaluation of elastic moduli of laminate fiber-reinforced composite materials is important for a permanent health monitoring of engineering structures in order to control their time-dependent degradation and failure prevention. For this purposes, the method of elastic modulus reconstruction via the minimization of discrepancy between the measured and calculated dispersion curves of the first fundamental symmetric and antisymmetric (S0 and A0) Lamb modes has been earlier developed and experimentally tested. It provided the values of all elastic parameters of the prepregs constituting a unidirectional or cross-ply composite plate; however, the Young modulus\( E_{y} \) was obtained with lower accuracy. To improve this point, the enhancement, based on the accounting for the zero group velocity effect, is proposed and experimentally validated.