Agreed that early radial tires could have a problem if the direction of rotation was reversed but that is no longer a problem. If you want to know which way the tires rotated originally then try this:
With the rim/tire held vertically and with the outside facing you, brush your fingers in both directions along the top of the tire tread. You should feel more roughness in one direction. The direction that your fingers move when they feel more roughness is the direction the top of that tire moved while it was turning when the vehicle was moving forward. If both tires turn out the same, then one was installed backwards on it's new wheel. If the tires had whitewalls, then that will not have happened.
Knowing the original rotational direction, I would reverse the direction to even out tread wear.