Most all of those parts will be imported copies. The quality is not the same. For instance... the chrome plate on the cool bore pistons is thinner and doesn't cover the piston as well as factory. rods and ringsets aren't the same finish as the originals and seem to wear faster.
Oregon, stens, rotary, sunbelt, aftermarket parts suppliers most mower shops use them, but if you ask they can probably get the OEM parts. They are going to more expensive, but if you are keeping the engine for yourself its worth it.