Can I swap one set of .030 over pistons for another, without machine work?

cast, hypereutectic and forged all use different piston to cylinder wall clearance. They also all have very different weights which will effect balance. Best bet would be to take bare block, old pistons w rods, crank, balancer, flex/fly and new pistons to competent machine shop and see what they say. Might only be a hundred or so to install new pistons with balance,assumingnthey are close to same weight.