This paper complements a previous study of the isotropic and nematic phases
of the Gay-Berne liquid-crystal model [Mehri et al., Phys. Rev. E 105, 064703
(2022)] with a study of its smectic B phase found at high density and low
temperatures. We find also in this phase strong correlations between the virial
and potential-energy thermal fluctuations, reflecting hidden scale invariance
and implying the existence of isomorphs. The predicted approximate isomorph
invariance of the physics is confirmed by simulations of the standard and
orientational radial distribution functions, the mean-square displacement as a
function of time, as well as the force, torque, velocity, angular velocity, and
orientational time-autocorrelation functions. The regions of the Gay-Berne
model that are relevant for liquid-crystal experiments can thus fully be
simplified via the isomorph theory