stroker engine balancing

Don't know bout you dismantler , but I need a simple answer. I got H rods I am looking at , a cast 3.58" crank, in a 340 block..asking, can I use flat top forged pistons without taking it to the machinist to balance. Would it be considered internally or externally balanced,?
You don't have a grinder around to do the balance job yourself? Might come in handy to turn the mains down on your 360 crank as well.