Well since that engine is now over 50 years old I would think it may have been rebuilt at one time or another. Would replacement pistons have the same design issues as the originals? I haven't even heard the engine run yet but was told it ran 2 years ago and it's not seized so I don't think it'll take much to get it going. It looks all stock and original to me, right down the the generator and canister oil filter and 2 bbl carb.