Swendsen-Wang random surface dynamics for Z2 and Z3 gauge theories in 2 + 1 dimensions is applied to the finite-temperature deconfining transition, and the static universality conjecture of Svetitsky and Yaffe is extended to the exponent z for critical dynamics. Our new dynamic universality conjecture (z(RS)d + 1 = z(SW)d) is supported both by a qualitative argument and by numerical simulations that show that the dynamic critical exponents for (2 + 1)-dimensional gauge theories (logarithmic or z(RS) < 0.3 +/- 0.1 and 0.53 +/- 0.03 for Z2 and Z3, respectively) are consistent with the values for the two-dimensional Ising-Potts models (logarithmic or z(SW) = 0.20-0.27 and 0.55 +/- 0.03 for Z2 and Z3, respectively) at the finite-temperature transition.