No offense, but if you rely on the mfr.'s recommendation, or lack thereof in this case, that's pretty dumb. Do you also believe in "lifetime" fluids? All that just defies common sense.

Even if the tires are staggered, if they're not directional, you can still rotate them left-right.

Rotating tires helps reduce irregular tire wear. Unless you have "lifetime tires," no reason not to rotate if you can.