Will Rod swap require balancing?

It's a gamble. BUT......since you are rebuilding the engine and using "stock style pistons", which sound like aftermarket, you will probably need to rebalance the whole rotating assembly anyway. You might get lucky there too IF the weight is the same. But even if the overall rod weight is the same, the ends may not weigh the same! Piston or either end of the rod, the further away from the crank centerline it is, the more the weight difference will affect balance.