I did a rebuild on a engine that was left full of water. Tore it all the way down, bore out another .020, it was already at .020 so now it's .040. New pistons and rings. In my engine's case it was a fresh rebuild that the previous owner let fill up with water. A couple of cylinder's were so bad they looked 100 years old. Like new with 20 over. I didn't replace any of the bearing inserts in it, nor the cam. Had the heads done since they were pretty rusty. End cost was under $700, gaskets, machine work and all.
Your pics look a lot better than my engine did. I would not be afraid at all of having it redone. Be as good as a new motor and half the cost. You would want the heads done, bored, the crank turned and all new bearings, core plugs, pistons and rings. Gaskets and seals and good to go.
Rick