Nope, since changing a watchface would imply a settings change and those aren't allowed by 3rd parties (unless you root the system and used modified apps, which no one has done for the watch as there isn't such a niche). Only one that comes to mind is Facer, which allows you to randomize the watchface, but it does so only with Facer watchfaces (which some are free and pretty good), not the stock ones.