My vote is for balancing. It only can help with the ride and tire longevity and certainly can't hurt. The factory tires on my trailer weren't balanced and I didn't notice any ill effects, however, when I upgraded to my set of Maxxis tires, I had America's (aka Discount) Tire balance them. They only charged a couple bucks a corner, which includes lifetime balancing, so each time I have them rotated, they will check and rebalance as necessary. For the price of a new set of tires, I figured 8 extra bucks is nothing...
A lot of times torque specs will be printed on a sticker right above the wheels or perhaps the ID sticker somewhere on the front of the trailer.