The RE050A does have an asymmetric tread pattern, but it remains in the same proper orientation when you just switch the wheel/tire from one side to the other.

I've never read anything that says that they are unidirectional, but if they were, you'd have to dismount them and flip them on the rims in order to move tires from one side to the other and retain the same water evacuation pattern.

I'd listen to Tire Rack Jim on this one.