An interesting question.
The first thing that I would do would be to examine all of the printing that's molded into the tire sidewall to see if a direction-of-rotation is indicated.
Years ago I read somewhere that, as a general rule, tires should be installed so the triangle shaped tread elements at the top of the tire point toward the front on the front tire and toward the rear on the back tire.
Personally, however, I find the fung shui harmony is disrupted unless the triangle tread elements, both front and rear, point toward the front so that's what I do.
From a functional engineering point of view, I doubt it matters very much if at all.